revert accidental change to uniswapv3 compute

reference hop index to determine the taker for an otc multihop
remove reference to tokens[] as its not used anymore
2023-02-23 19:03:47 -05:00 · 2023-02-23 18:59:07 -05:00 · 2023-02-23 17:42:38 -05:00 · 2023-02-23 15:59:37 -05:00 · 2023-02-23 15:20:48 -05:00 · 2023-02-23 15:19:49 -05:00
3045 changed files with 152066 additions and 206020 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,408 +0,0 @@
-version: 2
-
-jobs:
-    build:
-        resource_class: medium+
-        docker:
-            - image: circleci/node:9-browsers
-        environment:
-            CONTRACTS_COMMIT_HASH: '9ed05f5'
-        working_directory: ~/repo
-        steps:
-            - checkout
-            - run: echo 'export PATH=$HOME/CIRCLE_PROJECT_REPONAME/node_modules/.bin:$PATH' >> $BASH_ENV
-            - run:
-                  name: install-yarn
-                  command: sudo npm install --global yarn@1.9.4
-            - run:
-                  name: yarn
-                  command: yarn --frozen-lockfile --ignore-engines install
-            - run: yarn build:ci:no_website
-            - run: yarn build:ts
-            - save_cache:
-                  key: repo-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo
-    build-website:
-        resource_class: medium+
-        docker:
-            - image: circleci/node:9-browsers
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: cd packages/website && yarn build:prod
-    test-contracts-ganache:
-        docker:
-            - image: circleci/node:9-browsers
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn wsrun test:circleci @0x/contracts-multisig
-            - run: yarn wsrun test:circleci @0x/contracts-utils
-            - run: yarn wsrun test:circleci @0x/contracts-libs
-            - run: yarn wsrun test:circleci @0x/contracts-tokens
-            - run: yarn wsrun test:circleci @0x/contracts-extensions
-            - run: yarn wsrun test:circleci @0x/contracts-protocol
-    test-contracts-geth:
-        docker:
-            - image: circleci/node:9-browsers
-            - image: 0xorg/devnet
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            # HACK(albrow): we need to sleep 10 seconds to ensure the devnet is
-            # initialized
-            - run: sleep 10 && TEST_PROVIDER=geth yarn wsrun test @0x/contracts-multisig
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-utils
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-libs
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-tokens
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-extensions
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-protocol
-    test-publish:
-        resource_class: medium+
-        docker:
-            - image: circleci/node:9-browsers
-            - image: 0xorg/verdaccio
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn test:publish:circleci
-    test-doc-generation:
-        docker:
-            - image: circleci/node:9-browsers
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn test:generate_docs:circleci
-    test-pipeline:
-        docker:
-            - image: circleci/node:9
-            - image: postgres:11-alpine
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: ZEROEX_DATA_PIPELINE_TEST_DB_URL='postgresql://postgres@localhost/postgres' yarn wsrun test:circleci @0x/pipeline
-            - save_cache:
-                  key: coverage-pipeline-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/pipeline/coverage/lcov.info
-    test-rest:
-        docker:
-            - image: circleci/node:9-browsers
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn wsrun test:circleci @0x/contracts-test-utils
-            - run: yarn wsrun test:circleci @0x/abi-gen
-            - run: yarn wsrun test:circleci @0x/assert
-            - run: yarn wsrun test:circleci @0x/base-contract
-            - run: yarn wsrun test:circleci @0x/connect
-            - run: yarn wsrun test:circleci @0x/contract-wrappers
-            - run: yarn wsrun test:circleci @0x/dev-utils
-            - run: yarn wsrun test:circleci @0x/json-schemas
-            - run: yarn wsrun test:circleci @0x/metacoin
-            - run: yarn wsrun test:circleci @0x/order-utils
-            - run: yarn wsrun test:circleci @0x/order-watcher
-            - run: yarn wsrun test:circleci @0x/sol-compiler
-            - run: yarn wsrun test:circleci @0x/sol-tracing-utils
-            - run: yarn wsrun test:circleci @0x/sol-doc
-            - run: yarn wsrun test:circleci @0x/subproviders
-            - run: yarn wsrun test:circleci @0x/web3-wrapper
-            - run: yarn wsrun test:circleci @0x/utils
-            - run: yarn wsrun test:circleci @0x/instant
-            - save_cache:
-                  key: coverage-abi-gen-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/abi-gen/coverage/lcov.info
-            - save_cache:
-                  key: coverage-assert-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/assert/coverage/lcov.info
-            - save_cache:
-                  key: coverage-base-contract-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/base-contract/coverage/lcov.info
-            - save_cache:
-                  key: coverage-connect-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/connect/coverage/lcov.info
-            - save_cache:
-                  key: coverage-contract-wrappers-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/contract-wrappers/coverage/lcov.info
-            - save_cache:
-                  key: coverage-dev-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/dev-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/json-schemas/coverage/lcov.info
-            - save_cache:
-                  key: coverage-metacoin-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/metacoin/coverage/lcov.info
-            - save_cache:
-                  key: coverage-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/order-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-order-watcher-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/order-watcher/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-compiler-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-compiler/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-tracing-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-tracing-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-doc-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-doc/coverage/lcov.info
-            - save_cache:
-                  key: coverage-subproviders-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/subproviders/coverage/lcov.info
-            - save_cache:
-                  key: coverage-web3-wrapper-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/web3-wrapper/coverage/lcov.info
-    test-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-            - image: 0xorg/ganache-cli:2.2.2
-            - image: 0xorg/launch-kit-ci
-              command: |
-                  yarn start:ts -p 3000:3000
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      cd python-packages
-                      python -m ensurepip
-                      ./install
-            - save_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - '/usr/local/bin'
-                      - '/usr/local/lib/python3.7/site-packages'
-            - run:
-                  command: |
-                      cd python-packages
-                      ./cmd_pkgs_in_dep_order.py coverage run setup.py test
-            - save_cache:
-                  key: coverage-python-contract-addresses-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_addresses/.coverage
-            - save_cache:
-                  key: coverage-python-contract-artifacts-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_artifacts/.coverage
-            - save_cache:
-                  key: coverage-python-contract-demo-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_demo/.coverage
-            - save_cache:
-                  key: coverage-python-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/json_schemas/.coverage
-            - save_cache:
-                  key: coverage-python-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/order_utils/.coverage
-            - save_cache:
-                  key: coverage-python-sra-client-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/sra_client/.coverage
-    test-rest-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      cd python-packages/order_utils
-                      python -m ensurepip
-                      python -m pip install .
-            - save_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - '/usr/local/bin'
-                      - '/usr/local/lib/python3.7/site-packages'
-                      - '.eggs'
-                      - '.mypy_cache'
-                      - '.pytest_cache'
-                      - '.tox'
-            - run:
-                  command: |
-                      cd python-packages/order_utils
-                      tox
-    static-tests-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      python -m ensurepip
-                      cd python-packages
-                      ./install
-                      ./lint
-    static-tests:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/node:9-browsers
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn lerna run lint
-            - run: yarn prettier:ci
-            - run: cd packages/0x.js && yarn build:umd:prod
-            - run: yarn bundlewatch
-    submit-coverage:
-        docker:
-            - image: circleci/node:9-browsers
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-abi-gen-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-assert-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-base-contract-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-connect-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-contract-wrappers-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-dev-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-metacoin-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-order-watcher-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-compiler-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-tracing-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-doc-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-subproviders-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-web3-wrapper-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-contracts-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-addresses-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-artifacts-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-demo-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-sra-client-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn report_coverage
-workflows:
-    version: 2
-    main:
-        jobs:
-            - build
-            - build-website:
-                  requires:
-                      - build
-            - test-contracts-ganache:
-                  requires:
-                      - build
-            - test-contracts-geth:
-                  requires:
-                      - build
-            - test-pipeline:
-                  requires:
-                      - build
-            - test-rest:
-                  requires:
-                      - build
-            - static-tests:
-                  requires:
-                      - build
-            - test-publish:
-                  requires:
-                      - build
-            - test-doc-generation:
-                  requires:
-                      - build
-            - submit-coverage:
-                  requires:
-                      - test-rest
-                      - test-python
-            - static-tests-python:
-                  requires:
-                      - test-python
-            - test-python
-            # skip python tox run for now, as we don't yet have multiple test environments to support.
-            #- test-rest-python
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,7 +1,4 @@
 *.sol linguist-language=Solidity

 # Automatically collapse generated files in GitHub.
-*.svg linguist-generated
-packages/contract-artifacts/artifacts/*json linguist-generated
-packages/abi-gen-wrappers/wrappers/*.ts liguist-generated
-
+*.svg linguist-generated=true
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -0,0 +1,18 @@
+# See https://help.github.com/articles/about-codeowners/
+
+# for more info about CODEOWNERS file
+
+# It uses the same pattern rule for gitignore file
+
+# https://git-scm.com/docs/gitignore#_pattern_format
+
+# Dev tools & setup
+
+.github/ @dekz
+packages/contract-addresses/ @dekz @dextracker @kyu-c
+packages/contract-artifacts/ @dekz
+packages/protocol-utils/ @dekz
+
+# Protocol/smart contracts
+
+contracts/ @dekz @dextracker
--- a/.github/CODE_OF_CONDUCT.md
+++ b/.github/CODE_OF_CONDUCT.md
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -0,0 +1,91 @@
+## 0x Contribution Guide
+
+We welcome contributions from anyone on the internet and are grateful for even the smallest contributions. This document will help get you setup to start contributing back to 0x.
+
+### Getting started
+
+1.  Fork `0xproject/0x-tools`
+2.  Clone your fork
+3.  Follow the [installation & build steps](https://github.com/0xProject/0x-tools#install-dependencies) in the repo's top-level README.
+4.  Setup the recommended [Development Tooling](#development-tooling).
+5.  Open a [draft PR](https://github.blog/2019-02-14-introducing-draft-pull-requests/) against the `development` branch and describe the change you are intending to undertake in the PR description. (see [our branch naming conventions](#branch-structure))
+
+Before making the PR "Ready for review", make sure:
+
+-   It passes our linter checks (`yarn lint`)
+-   It is properly formatted with Prettier (`yarn prettier`)
+-   It passes our continuous integration tests (See: [Enabling code coverage checks on your fork](#fix-submit-coverage-ci-failure) for instructions on getting the `submit-coverage` test to pass on forks)
+-   You've created/updated the corresponding [CHANGELOG](#CHANGELOGs) entries.
+-   Your changes have sufficient test coverage (e.g regression tests have been added for bug fixes)
+
+### Branch structure
+
+We have two main branches:
+
+-   `master` represents the most recently released (published on npm) version of the codebase.
+-   `development` represents the current development state of the codebase.
+
+ALL PRs should be opened against `development`.
+
+Branch names should be prefixed with `fix`, `feature` or `refactor`.
+
+-   e.g `fix/missing-import`
+-   If the PR only edits a single package, add it's name too
+    -   e.g `fix/subproviders/missing-import`
+
+### CHANGELOGs
+
+At 0x we use [Semantic Versioning](http://semver.org/) for all our published packages. If a change you make corresponds to a semver bump, you must modify the package's `CHANGELOG.json` file accordingly.
+
+Each CHANGELOG entry that corresponds to a published package will have a `timestamp`. If no entry exists without a `timestamp`, you must first create a new one:
+
+```
+{
+        "version": "1.0.1", <- The updated package version
+        "changes": [
+            {
+                "note": "", <- Describe your change
+                "PR": 100 <- Your PR number
+            }
+        ]
+    },
+```
+
+If an entry without a `timestamp` already exists, this means other changes have been introduced by other collaborators since the last publish. Add your changes to the list of notes and adjust the version if your PR introduces a greater semver change (i.e current changes required a patch bump, but your changes require a major version bump).
+
+### Development Tooling
+
+We strongly recommend you use the [VSCode](https://code.visualstudio.com/) text editor since most of our code is written in TypeScript and it offers amazing support for the language.
+
+#### Linter
+
+We use [ESLint](https://eslint.org/docs/latest/) to keep our code-style consistent.
+
+Use `yarn lint` to lint the entire monorepo, and `PKG={PACKAGE_NAME} yarn lint` to lint a specific package.
+
+Integrate it into your text editor:
+
+-   VSCode: [ESLint](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint)
+-   Atom: [ESLint](https://atom.io/packages/eslint)
+
+#### Auto-formatter
+
+We use [Prettier](https://prettier.io/) to auto-format our code. Be sure to either add a [text editor integration](https://prettier.io/docs/en/editors.html) or a [pre-commit hook](https://prettier.io/docs/en/precommit.html) to properly format your code changes.
+
+If using the Atom text editor, we recommend you install the following packages:
+
+-   VSCode: [prettier-vscode](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode)
+-   Atom: [prettier-atom](https://atom.io/packages/prettier-atom)
+
+## Unenforced coding conventions
+
+A few of our coding conventions are not yet enforced by the linter/auto-formatter. Be careful to follow these conventions in your PR's.
+
+1.  Unused anonymous function parameters should be named with an underscore + number (e.g \_1, \_2, etc...)
+1.  There should be a new-line between methods in a class and between test cases.
+1.  If a string literal has the same value in two or more places, it should be a single constant referenced in both places.
+1.  Do not import from a project's `index.ts` (e.g import { Token } from '../src';). Always import from the source file itself.
+1.  Generic error variables should be named `err` instead of `e` or `error`.
+1.  If you _must_ cast a variable to any - try to type it back as fast as possible. (e.g., `const cw = ((zeroEx as any)._contractWrappers as ContractWrappers);`). This ensures subsequent code is type-safe.
+1.  Our enum conventions coincide with the recommended TypeScript conventions, using capitalized keys, and all-caps snake-case values. Eg `GetStats = 'GET_STATS'`
+1.  All public, exported methods/functions/classes must have associated Javadoc-style comments.
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -2,15 +2,13 @@

 <!--- Before submitting please check to see if this issue was already reported -->

-<!--- Provide a general summary of the issue in the Title above -->
-
 ## Expected Behavior

 <!--- If you're describing a bug, tell us what should happen -->

 <!--- If you're suggesting a package change/improvement, tell us how it should work -->

-<!--- If you're suggesting a contract or protocol change/improvement, visit our ZEIPs repo -->
+<!--- If you're suggesting a contract or protocol change/improvement, visit our ZEIPs repo https://github.com/0xProject/ZEIPs -->

 ## Current Behavior

@@ -49,10 +47,9 @@
 | Package | Version |
 | ------: | :------ |

-
 <!-- For example:
-|             `0x.js` | 2.0.4   |
-| `Exchange Contract` | v2      |
+|    `protocol-utils` | 2.0.4   |
+| `Exchange Contract` | v3      |
 -->

 | Network |
@@ -61,6 +58,6 @@

 <!-- For example:
 | mainnet |
-| kovan |
-| testrpc |
+| goerli |
+| development |
 -->
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -20,7 +20,6 @@

 <!--- The following points should be used to indicate the progress of your PR.  Put an `x` in all the boxes that apply right now, and come back over time and check them off as you make progress.  If you're unsure about any of these, don't hesitate to ask. We're here to help! -->

-   [ ] Prefix PR title with `[WIP]` if necessary.
 -   [ ] Add tests to cover changes as needed.
 -   [ ] Update documentation as needed.
 -   [ ] Add new entries to the relevant CHANGELOG.jsons.
--- a/.github/autolabeler.yml
+++ b/.github/autolabeler.yml
@@ -1,42 +1,2 @@
-python: ['python-packages']
-contracts: ['contracts']
-sol-doc: ['packages/sol-doc']
-sol-resolver: ['packages/sol-resolver']
-sra-spec: ['packages/sra-spec']
-subproviders: ['packages/subproviders']
-contract-addresses: ['packages/contract-addresses']
-migrations: ['packages/migrations']
-web3-wrapper: ['packages/web3-wrapper']
-sol-compiler: ['packages/sol-compiler']
-types: ['packages/types']
-instant: ['packages/instant']
-abi-gen-templates: ['packages/abi-gen-templates']
-abi-gen: ['packages/abi-gen']
-website: ['packages/website']
-sol-coverage: ['packages/sol-coverage']
-sol-profiler: ['packages/sol-profiler']
-sol-trace: ['packages/sol-trace']
-sol-tracing-utils: ['packages/sol-tracing-utils']
-utils: ['packages/utils']
-tslint-config: ['packages/tslint-config']
-asset-buyer: ['packages/asset-buyer']
-order-watcher: ['packages/order-watcher']
-react-docs: ['packages/react-docs']
-order-utils: ['packages/order-utils']
-react-shared: ['packages/react-shared']
-assert: ['packages/assert']
-base-contract: ['packages/base-contract']
-typescript-typings: ['packages/typescript-typings']
-0x.js: ['packages/0x.js']
-abi-gen-wrappers: ['packages/abi-gen-wrappers']
-metacoin: ['packages/metacoin']
-contract-artifacts: ['packages/contract-artifacts']
-dev-utils: ['packages/dev-utils']
-contract-wrappers: ['packages/contract-wrappers']
-json-schemas: ['packages/json-schemas']
-ethereum-types: ['ethereum-types']
-connect: ['packages/connect']
-fill-scenarios: ['packages/fill-scenarios']
-dev-tools-pages: ['packages/dev-tools-pages']
-testnet-faucets: ['packages/testnet-faucets']
-monorepo-scripts: ['packages/monorepo-scripts']
+documentation: ['docs']
+liquidity integrations: ['contracts/zero-ex/contracts/src/transformers']
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -0,0 +1,7 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: monthly
+    target-branch: "development"
--- a/.github/stale.yml
+++ b/.github/stale.yml
@@ -1,19 +0,0 @@
-# Number of days of inactivity before an issue becomes stale
-daysUntilStale: 30
-# Number of days of inactivity before a stale issue is closed
-daysUntilClose: 30
-# Issues with these labels will never be considered stale
-exemptLabels:
-    - pinned
-    - security
-# Label to use when marking an issue as stale
-staleLabel: stale
-# Comment to post when marking an issue as stale. Set to `false` to disable
-markComment: >
-    This issue has been automatically marked as stale because it has not had
-    recent activity. It will be closed if no further activity occurs. Thank you
-    for your contributions.
-# Comment to post when closing a stale issue. Set to `false` to disable
-closeComment: >
-    This issue has been automatically closed because no activity occured in 7 days after being marked as stale. If it's still relevant - feel free to reopen. Thank you
-    for your contributions.
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,137 @@
+name: Continuous Integration
+on:
+    push:
+        branches:
+            - main
+            - development
+    pull_request:
+
+jobs:
+    build:
+        name: Build and test
+        runs-on: ubuntu-latest
+        env:
+            ARBITRUM_RPC_URL: ${{ secrets.ARBITRUM_RPC_URL }}
+            AVALANCHE_RPC_URL: ${{ secrets.AVALANCHE_RPC_URL }}
+            BSC_RPC_URL: ${{ secrets.BSC_RPC_URL }}
+            FANTOM_RPC_URL: ${{ secrets.FANTOM_RPC_URL }}
+            MAINNET_RPC_URL: ${{ secrets.MAINNET_RPC_URL }}
+            OPTIMISM_RPC_URL: ${{ secrets.OPTIMISM_RPC_URL }}
+            POLYGON_RPC_URL: ${{ secrets.POLYGON_RPC_URL }}
+        steps:
+            - uses: actions/checkout@v3
+              with:
+                  submodules: recursive
+
+            - name: Setup Node
+              uses: actions/setup-node@v3
+              with:
+                  node-version: '16'
+
+            - name: Install dependencies
+              run: yarn install --frozen-lockfile
+
+            - name: Build solution
+              run: yarn build
+
+            - name: Lint typescript
+              run: yarn lint:ts
+
+            - name: Lint solidity
+              run: yarn lint:contracts
+
+            - name: Run prettier
+              run: yarn prettier:ci
+
+            - name: Check dependent packages have consistent versions
+              run: yarn deps_versions:ci
+
+            - name: Check diff in docs
+              run: yarn diff_md_docs:ci
+
+            - name: Check for broken links in markdown files
+              run: yarn test:links
+
+            - name: Test doc generation
+              run: yarn test:generate_docs:ci
+
+            - name: Test @0x/contracts-*
+              run: |
+                  yarn wsrun \
+                    -p @0x/contracts-multisig \
+                    -p @0x/contracts-utils \
+                    -p @0x/contracts-exchange-libs \
+                    -p @0x/contracts-erc721 \
+                    -p @0x/contracts-erc1155 \
+                    -p @0x/contracts-asset-proxy \
+                    -p @0x/contracts-broker \
+                    -p @0x/contracts-zero-ex \
+                    -m --serial -c test:ci
+
+            - name: Test local @0x/contracts-*
+              run: |
+                  yarn wsrun \
+                    -p @0x/contracts-test-utils \
+                    -p @0x/contract-addresses \
+                    -p @0x/contract-artifacts \
+                    -p @0x/contract-wrappers-test \
+                    -p @0x/order-utils \
+                    -m --serial -c test:ci
+
+            - name: Add foundry
+              uses: foundry-rs/foundry-toolchain@v1
+              with:
+                  version: nightly
+
+            - name: Run Forge build for erc20
+              working-directory: contracts/erc20
+              run: |
+                  forge --version
+                  forge build --sizes
+
+            - name: Run Forge tests for erc20
+              working-directory: contracts/erc20
+              run: |
+                  forge test -vvv --gas-report
+
+            - name: Run Forge coverage for erc20
+              working-directory: contracts/erc20
+              run: |
+                  forge coverage --report summary --report lcov
+
+            - name: Upload the coverage report to Coveralls
+              uses: coverallsapp/github-action@master
+              with:
+                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  base-path: ./contracts/erc20/
+                  path-to-lcov: ./contracts/erc20/lcov.info
+
+            - name: Run Forge build for zero-ex
+              working-directory: contracts/zero-ex
+              run: |
+                  forge --version
+                  forge build --sizes
+
+            - name: Run Forge tests for zero-ex
+              working-directory: contracts/zero-ex
+              run: |
+                  forge test -vvv --gas-report
+
+            - name: Run Forge coverage for zero-ex
+              working-directory: contracts/zero-ex
+              run: |
+                  forge coverage --report summary --report lcov
+
+            - name: Upload the coverage report to Coveralls
+              uses: coverallsapp/github-action@master
+              with:
+                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  base-path: ./contracts/zero-ex/
+                  path-to-lcov: ./contracts/zero-ex/lcov.info
+
+            - name: Check coverage threshold
+              uses: VeryGoodOpenSource/very_good_coverage@v2
+              with:
+                  path: ./contracts/zero-ex/lcov.info
+                  min_coverage: 6.98
+                  exclude: '**/tests'
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,53 @@
+name: publish
+
+on:
+  workflow_dispatch:
+      inputs:
+          ci_status:
+              description: 'required CI status'
+              default: 'success'
+              required: true
+          prerelease:
+              description: 'prerelease name'
+              required: false
+
+jobs:
+    publish:
+        runs-on: ubuntu-latest
+        steps:
+            - name: 'check successful status'
+              run: |
+                  REF_STATUS=$(curl -s \
+                  'https://api.github.com/repos/${{ github.repository }}/commits/${{ github.ref }}/status' \
+                  | jq .state)
+                  [[ "${REF_STATUS}" == '"${{ github.event.inputs.ci_status }}"' ]] || \
+                  (echo "::error ::${{ github.ref }} does not have a successful CI status" && false)
+            - uses: actions/checkout@v2
+              with:
+                ref: ${{ github.ref }}
+                fetch-depth: 0
+            - uses: actions/setup-node@v1
+              with:
+                node-version: 16
+            - uses: actions/setup-python@v2
+            - name: 'configure git'
+              run: |
+                  git config --global user.email "github-actions@github.com"
+                  git config --global user.name "Github Actions"
+            - name: 'install dependencies'
+              run: |
+                  yarn -D
+            - name: 'build and publish'
+              run: |
+                  echo '//registry.npmjs.org/:_authToken=${NPM_TOKEN}' > .npmrc
+                  npm run run:publish:gha
+              env:
+                  NPM_TOKEN: ${{ secrets.NPM_PUBLISH_TOKEN }}
+                  GITHUB_TOKEN: ${{ github.token }}
+                  PUBLISH_PRERELEASE: ${{ github.event.inputs.prerelease }}
+            - name: 'merge into main branch'
+              if: github.event.inputs.prerelease == '' # unless it's a prerelease
+              run: |
+                  git checkout main && \
+                  git merge ${{ github.ref }} && \
+                  git push
--- a/.github/workflows/stale.yml
+++ b/.github/workflows/stale.yml
@@ -0,0 +1,40 @@
+name: "Close stale issues and PRs"
+on:
+  schedule:
+    - cron: "0 8 * * 1-5" # This is in UTC.
+  # Do a dry-run (debug-only: true) whenever this workflow itself is changed.
+  pull_request:
+    paths:
+      - .github/workflows/stale.yml
+    types:
+      - opened
+      - synchronize
+
+permissions:
+  issues: write
+  pull-requests: write
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v7
+        with:
+          ascending: true # Spend API operations budget on older, more-likely-to-get-closed issues first
+          close-issue-message: "" # Leave no comment when closing
+          close-pr-message: "" # Leave no comment when closing
+          days-before-issue-stale: 30
+          days-before-pr-stale: 30
+          days-before-close: 14
+          debug-only: ${{ github.event_name == 'pull_request' }} # Dry-run when true.
+          exempt-issue-labels: bug,enhancement,feature,question
+          # No actual changes get made in debug-only mode, so we can raise the operations ceiling.
+          operations-per-run: ${{ github.event_name == 'pull_request' && 100 || 30}}
+          stale-issue-label: stale
+          stale-issue-message: "This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions."
+          stale-pr-label: stale
+          stale-pr-message: "This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions."
+          # Time immemorial when in debug-only mode (ie. on pull requests).
+          # `STALEBOT_START_DATE` otherwise.
+          # You can use this as a killswitch by setting `STALEBOT_START_DATE` in the far future.
+          start-date: ${{ github.event_name == 'pull_request' && '1970-01-01T00:00:00Z' || secrets.STALEBOT_START_DATE }} # ISO 8601 or RFC 2822
--- a/.gitignore
+++ b/.gitignore
@@ -15,9 +15,6 @@ pids
 *.db
 *.sqlite

-# Directory for instrumented libs generated by jscoverage/JSCover
-lib-cov
-
 # Coverage directory used by tools like istanbul
 coverage

@@ -40,9 +37,12 @@ build/Release
 node_modules/
 jspm_packages/

-# Typescript v1 declaration files
+# TypeScript v1 declaration files
 typings/

+# NVM config
+.nvmrc
+
 # Optional npm cache directory
 .npm
 .npmrc
@@ -72,52 +72,35 @@ generated_docs/

 TODO.md

-# VSCode file
+# IDE file
 .vscode
-
-packages/website/public/bundle*
-packages/dev-tools-pages/public/bundle*
-packages/react-docs/example/public/bundle*
-
-# server cli
-packages/testnet-faucets/server/
+.idea

 # generated contract artifacts/
-contracts/protocol/generated-artifacts/
-contracts/multisig/generated-artifacts/
-contracts/utils/generated-artifacts/
-contracts/libs/generated-artifacts/
-contracts/interfaces/generated-artifacts/
-contracts/tokens/generated-artifacts/
-contracts/examples/generated-artifacts/
-contracts/extensions/generated-artifacts/
-packages/sol-tracing-utils/test/fixtures/artifacts/
-packages/metacoin/artifacts/
+generated-artifacts/

 # generated contract wrappers
-packages/abi-gen-wrappers/wrappers
-contracts/protocol/generated-wrappers/
-contracts/multisig/generated-wrappers/
-contracts/utils/generated-wrappers/
-contracts/libs/generated-wrappers/
-contracts/interfaces/generated-wrappers/
-contracts/tokens/generated-wrappers/
-contracts/examples/generated-wrappers/
-contracts/extensions/generated-wrappers/
-packages/metacoin/src/contract_wrappers
+generated-wrappers/

-# solc-bin in sol-compiler
-packages/sol-compiler/solc_bin/
+# forge std-lib
+contracts/zero-ex/contracts/deps/forge-std

-# Monorepo scripts
-packages/*/scripts/
+# foundry artifacts
+foundry-artifacts/

-# python stuff
-.eggs
-.mypy_cache
-.tox
-python-packages/*/build
-python-packages/*/dist
-__pycache__
-python-packages/*/src/*.egg-info
-python-packages/*/.coverage
+# foundry cache
+cache/
+
+#foundry output artifacts
+out/
+
+# typechain wrappers
+contracts/zero-ex/typechain-wrappers/
+
+# Doc README copy
+packages/*/docs/README.md
+
+.DS_Store
+
+# the snapshot that gets built for migrations sure does have a ton of files
+packages/migrations/0x_ganache_snapshot*
--- a/.gitmodules
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "contracts/zero-ex/contracts/deps/forge-std"]
+	path = contracts/zero-ex/contracts/deps/forge-std
+	url = https://github.com/foundry-rs/forge-std
+[submodule "contracts/erc20/lib/forge-std"]
+	path = contracts/erc20/lib/forge-std
+	url = https://github.com/foundry-rs/forge-std
--- a/.husky/pre-commit
+++ b/.husky/pre-commit
@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+. "$(dirname -- "$0")/_/husky.sh"
+
+npx lint-staged --no-stash
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,33 +1,10 @@
 lib
+deps
 .nyc_output
-/contracts/protocol/generated-wrappers
-/contracts/protocol/generated-artifacts
-/contracts/multisig/generated-wrappers
-/contracts/multisig/generated-artifacts
-/contracts/utils/generated-wrappers
-/contracts/utils/generated-artifacts
-/contracts/libs/generated-wrappers
-/contracts/libs/generated-artifacts
-/contracts/interfaces/generated-wrappers
-/contracts/interfaces/generated-artifacts
-/contracts/tokens/generated-wrappers
-/contracts/tokens/generated-artifacts
-/contracts/examples/generated-wrappers
-/contracts/examples/generated-artifacts
-/contracts/extensions/generated-wrappers
-/contracts/extensions/generated-artifacts
-/packages/abi-gen-wrappers/src/generated-wrappers
-/packages/contract-artifacts/artifacts
-/python-packages/contract_artifacts/src/zero_ex/contract_artifacts/artifacts
-/packages/json-schemas/schemas
-/python-packages/json_schemas/src/zero_ex/json_schemas/schemas
-/packages/metacoin/src/contract_wrappers
-/packages/metacoin/artifacts
-/packages/sra-spec/public/
-/packages/dev-tools-pages/ts/**/data.json
+generated-artifacts/
+generated-wrappers/
+foundry-artifacts/
+out/
+cache/
 package.json
-scripts/postpublish_utils.js
-packages/sol-coverage/test/fixtures/artifacts
-.pytest_cache
-.mypy_cache
-.tox
+packages
--- a/.prettierrc
+++ b/.prettierrc
@@ -1,6 +1,20 @@
 {
-    "tabWidth": 4,
    "printWidth": 120,
-    "trailingComma": all,
-    "singleQuote": true
+    "tabWidth": 4,
+    "singleQuote": true,
+    "trailingComma": "all",
+    "bracketSpacing": true,
+    "arrowParens": "avoid",
+    "overrides": [
+        {
+          "files": "**/*.sol",
+          "options": {
+            "printWidth": 120,
+            "tabWidth": 4,
+            "useTabs": false,
+            "singleQuote": false,
+            "bracketSpacing": false
+          }
+        }
+      ]
 }
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -0,0 +1,23 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/conf.py
+
+# Build documentation with MkDocs
+#mkdocs:
+#  configuration: mkdocs.yml
+
+# Optionally build your docs in additional formats such as PDF
+#formats:
+#  - pdf
+
+# Optionally set the version of Python and requirements required to build your docs
+python:
+  version: 3.7
+  install:
+    - requirements: docs/requirements.txt
--- a/.solhint.json
+++ b/.solhint.json
@@ -0,0 +1,17 @@
+{
+    "extends": "solhint:recommended",
+    "plugins": ["prettier"],
+    "rules": {
+        "prettier/prettier": "error",
+        "avoid-low-level-calls": "off",
+        "avoid-tx-origin": "warn",
+        "code-complexity": "off",
+        "const-name-snakecase": "error",
+        "function-max-lines": ["error", 350],
+        "max-line-length": ["error", 120],
+        "no-inline-assembly": "off",
+        "quotes": ["error", "double"],
+        "no-empty-blocks": "off",
+        "compiler-version": "off"
+    }
+}
--- a/.solhintignore
+++ b/.solhintignore
@@ -0,0 +1,9 @@
+contracts/erc20/src/ZRXToken.sol
+node_modules/
+lib
+deps
+generated-artifacts/
+generated-wrappers/
+foundry-artifacts/
+out/
+cache/
--- a/38
+++ b/38
@@ -1,38 +0,0 @@
-# See https://help.github.com/articles/about-codeowners/
-# for more info about CODEOWNERS file
-
-# It uses the same pattern rule for gitignore file
-# https://git-scm.com/docs/gitignore#_pattern_format
-
-# Website
-packages/asset-buyer/  @BMillman19 @fragosti @steveklebanoff
-packages/instant/  @BMillman19 @fragosti @steveklebanoff
-packages/website/  @BMillman19 @fragosti @fabioberger @steveklebanoff
-
-# Dev tools & setup
-.circleci/ @LogvinovLeon
-packages/abi-gen/ @LogvinovLeon
-packages/base-contract/ @LogvinovLeon
-packages/connect/ @fragosti 
-packages/abi-gen-templates/ @LogvinovLeon
-packages/contract-addresses/ @albrow
-packages/contract-artifacts/ @albrow
-packages/dev-utils/ @LogvinovLeon @fabioberger
-packages/devnet/ @albrow
-packages/ethereum-types/ @LogvinovLeon
-packages/metacoin/ @LogvinovLeon
-packages/monorepo-scripts/ @fabioberger
-packages/order-utils/ @fabioberger @LogvinovLeon 
-packages/sol-compiler/ @LogvinovLeon
-packages/sol-coverage/ @LogvinovLeon
-packages/sol-profiler/ @LogvinovLeon
-packages/sol-trace/ @LogvinovLeon
-packages/sol-tracing-utils/ @LogvinovLeon
-packages/sol-resolver/ @LogvinovLeon
-packages/subproviders/ @fabioberger @dekz
-packages/verdaccio/ @albrow
-packages/web3-wrapper/ @LogvinovLeon @fabioberger
-python-packages/ @feuGeneA
-
-# Protocol/smart contracts
-contracts/core/test/ @albrow
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,105 +0,0 @@
-## 0x Contribution Guide
-
-We welcome contributions from anyone on the internet and are grateful for even the smallest contributions. This document will help get you setup to start contributing back to 0x.
-
-### Getting started
-
-1.  Fork `0xproject/0x-monorepo`
-2.  Clone your fork
-3.  Follow the [installation & build steps](https://github.com/0xProject/0x-monorepo#install-dependencies) in the repo's top-level README.
-4.  Setup the recommended [Development Tooling](#development-tooling).
-5.  Open a PR with the `[WIP]` flag against the `development` branch and describe the change you are intending to undertake in the PR description. (see [our branch naming conventions](#branch-structure))
-
-Before removing the `[WIP]` tag and submitting the PR for review, make sure:
-
-   It passes our linter checks (`yarn lint`)
-   It is properly formatted with Prettier (`yarn prettier`)
-   It passes our continuous integration tests (See: [Enabling code coverage checks on your fork](#enabling-code-coverage-checks-on-your-fork) for instructions on getting the `submit-coverage` test to pass on forks)
-   You've created/updated the corresponding [CHANGELOG](#CHANGELOGs) entries.
-   Your changes have sufficient test coverage (e.g regression tests have been added for bug fixes)
-
-### Branch structure
-
-We have two main branches:
-
-   `master` represents the most recently released (published on npm) version of the codebase.
-   `development` represents the current development state of the codebase.
-
-ALL PRs should be opened against `development`.
-
-Branch names should be prefixed with `fix`, `feature` or `refactor`.
-
-   e.g `fix/broken-wiki-link`
-   If the PR only edits a single package, add it's name too
-    -   e.g `fix/website/broken-wiki-link`
-
-### CHANGELOGs
-
-At 0x we use [Semantic Versioning](http://semver.org/) for all our published packages. If a change you make corresponds to a semver bump, you must modify the package's `CHANGELOG.json` file accordingly.
-
-Each CHANGELOG entry that corresponds to a published package will have a `timestamp`. If no entry exists without a `timestamp`, you must first create a new one:
-
-```
-{
-        "version": "1.0.1", <- The updated package version
-        "changes": [
-            {
-                "note": "", <- Describe your change
-                "PR": 100 <- Your PR number
-            }
-        ]
-    },
-```
-
-If an entry without a `timestamp` already exists, this means other changes have been introduced by other collaborators since the last publish. Add your changes to the list of notes and adjust the version if your PR introduces a greater semver change (i.e current changes required a patch bump, but your changes require a major version bump).
-
-### Development Tooling
-
-We strongly recommend you use the [VSCode](https://code.visualstudio.com/) text editor since most of our code is written in Typescript and it offers amazing support for the language.
-
-#### Linter
-
-We use [TSLint](https://palantir.github.io/tslint/) with [custom configs](https://github.com/0xProject/0x-monorepo/tree/development/packages/tslint-config) to keep our code-style consistent.
-
-Use `yarn:lint` to lint the entire monorepo, and `PKG={PACKAGE_NAME} yarn lint` to lint a specific package.
-
-If you want to change a rule, or add a custom rule, please make these changes to our [tslint-config](https://github.com/0xProject/0x-monorepo/tree/development/packages/tslint-config) package. All other packages have it as a dependency.
-
-Integrate it into your text editor:
-
-   VSCode: [vscode-tslint](https://marketplace.visualstudio.com/items?itemName=eg2.tslint)
-   Atom: [linter-tslint](https://atom.io/packages/linter-tslint)
-
-#### Auto-formatter
-
-We use [Prettier](https://prettier.io/) to auto-format our code. Be sure to either add a [text editor integration](https://prettier.io/docs/en/editors.html) or a [pre-commit hook](https://prettier.io/docs/en/precommit.html) to properly format your code changes.
-
-If using the Atom text editor, we recommend you install the following packages:
-
-   VSCode: [prettier-vscode](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode)
-   Atom: [prettier-atom](https://atom.io/packages/prettier-atom)
-
-## Unenforced coding conventions
-
-A few of our coding conventions are not yet enforced by the linter/auto-formatter. Be careful to follow these conventions in your PR's.
-
-1.  Unused anonymous function parameters should be named with an underscore + number (e.g \_1, \_2, etc...)
-1.  There should be a new-line between methods in a class and between test cases.
-1.  If a string literal has the same value in two or more places, it should be a single constant referenced in both places.
-1.  Do not import from a project's `index.ts` (e.g import { Token } from '../src';). Always import from the source file itself.
-1.  Generic error variables should be named `err` instead of `e` or `error`.
-1.  If you _must_ cast a variable to any - try to type it back as fast as possible. (e.g., `const cw = ((zeroEx as any)._contractWrappers as ContractWrappers);`). This ensures subsequent code is type-safe.
-1.  Our enum conventions coincide with the recommended Typescript conventions, using capitalized keys, and all-caps snake-case values. Eg `GetStats = 'GET_STATS'`
-1.  All public, exported methods/functions/classes must have associated Javadoc-style comments.
-
-### Fix `submit-coverage` CI failure
-
-If you simply fork the repo and then create a PR from it, your PR will fail the `submit-coverage` check on CI. This is because the 0x CircleCI configuration sets the `COVERALLS_REPO_TOKEN` environment variable to the token for `0xProject/0x-monorepo`, but when running the check against your fork the token needs to match your repo's name `your-username/0x-monorepo`.
-
-To facilitate this check, after creating your fork, but before creating the branch for your PR, do the following:
-
-1.  Log in to [coveralls.io](https://coveralls.io/), go to `Add Repos`, and enable your fork. Then go to the settings for that repo, and copy the `Repo Token` identifier.
-2.  Log in to [CircleCI](https://circleci.com/login), go to `Add Projects`, click the `Set Up Project` button corresponding to your fork, and then click `Start Building`. (Aside from step 3 below, no actual set up is needed, since it will use the `.circleci/config.yml` file in 0x-monorepo, so you can ignore all of the instruction/explanation given on the page with the `Start Building` button.)
-3.  In CircleCI, configure your project to add an environment variable, with name `COVERALLS_REPO_TOKEN`, and for the value paste in the `Repo Token` you copied in step 1.
-
-Now, when you push to your branch, CircleCI will automatically run all of the checks in your own instance, and the coverage check will work since it has the proper `Repo Token`, and the PR will magically refer to your own checks rather than running them in the 0x CircleCI instance.
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright 2017 ZeroEx Intl.
+Copyright 2020 ZeroEx Labs

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
--- a/README.md
+++ b/README.md
@@ -2,96 +2,45 @@

 ---

-[0x][website-url] is an open protocol that facilitates trustless, low friction exchange of Ethereum-based assets. For more information on how it works, check out the [0x protocol specification](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md).
+[0x][website-url] is an open protocol that facilitates trustless, low friction exchange of Ethereum-based assets. For more information on how it works, check out the [0x protocol specification](https://protocol.0x.org/).

 This repository is a monorepo including the 0x protocol smart contracts and numerous developer tools. Each public sub-package is independently published to NPM.

-If you're developing on 0x now or are interested in using 0x infrastructure in the future, please join our [developer mailing list][dev-mailing-list-url] for updates.
+[website-url]: https://0x.org

-[website-url]: https://0xproject.com
-[whitepaper-url]: https://0xproject.com/pdfs/0x_white_paper.pdf
-[dev-mailing-list-url]: http://eepurl.com/dx4cPf
-
-[![CircleCI](https://circleci.com/gh/0xProject/0x-monorepo.svg?style=svg&circle-token=61bf7cd8c9b4e11b132089dfcffdd1be277d1e0c)](https://circleci.com/gh/0xProject/0x-monorepo)
-[![Coverage Status](https://coveralls.io/repos/github/0xProject/0x-monorepo/badge.svg?branch=development)](https://coveralls.io/github/0xProject/0x-monorepo?branch=development)
-[![Discord](https://img.shields.io/badge/chat-rocket.chat-yellow.svg?style=flat)](https://chat.0xproject.com)
-[![Join the chat at https://gitter.im/0xProject/Lobby](https://badges.gitter.im/0xProject/Lobby.svg)](https://gitter.im/0xProject/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Coverage Status](https://coveralls.io/repos/github/0xProject/protocol/badge.svg?branch=development)](https://coveralls.io/github/0xProject/protocol?branch=development)
+[![Discord](https://img.shields.io/badge/chat-discord.chat-yellow.svg?style=flat)](https://discordapp.com/invite/d3FTX3M)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

 ## Packages

-Visit our [developer portal](https://0xproject.com/docs/order-utils) for a comprehensive list of core & community maintained packages. All packages maintained with this monorepo are listed below.
+Visit our [developer portal](https://0x.org/docs/) for a comprehensive list of core & community maintained packages. All packages maintained with this monorepo are listed below.

-### Python Packages
+### Solidity Packages

-| Package                                                        | Version                                                                                                             | Description                                                                                       |
-| -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
-| [`0x-contract-addresses`](/python-packages/contract_addresses) | [![PyPI](https://img.shields.io/pypi/v/0x-contract-addresses.svg)](https://pypi.org/project/0x-contract-addresses/) | A tiny utility library for getting known deployed contract addresses for a particular network     |
-| [`0x-contract-artifacts`](/python-packages/contract_artifacts) | [![PyPI](https://img.shields.io/pypi/v/0x-contract-artifacts.svg)](https://pypi.org/project/0x-contract-artifacts/) | 0x smart contract compilation artifacts                                                           |
-| [`0x-json-schemas`](/python-packages/json_schemas)             | [![PyPI](https://img.shields.io/pypi/v/0x-json-schemas.svg)](https://pypi.org/project/0x-json-schemas/)             | 0x-related JSON schemas                                                                           |
-| [`0x-order-utils`](/python-packages/order_utils)               | [![PyPI](https://img.shields.io/pypi/v/0x-order-utils.svg)](https://pypi.org/project/0x-order-utils/)               | A set of utilities for generating, parsing, signing and validating 0x orders                      |
-| [`0x-sra-client`](/python-packages/sra_client)                 | [![PyPI](https://img.shields.io/pypi/v/0x-sra-client.svg)](https://pypi.org/project/0x-sra-client/)                 | A Python client for interacting with servers conforming to the Standard Relayer API specification |
+These packages are all under development. See [/contracts/README.md](/contracts/README.md) for a list of deployed packages.

-### Typescript/Javascript Packages
+| Package                                             | Version                                                                                                                     | Description                                                          |
+| --------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------- |
+| [`@0x/contracts-zero-ex`](/contracts/zero-ex)       | [![npm](https://img.shields.io/npm/v/@0x/contracts-zero-ex.svg)](https://www.npmjs.com/package/@0x/contracts-zero-ex)       | The contracts used for settling trades within the protocol           |
+| [`@0x/contracts-erc20`](/contracts/erc20)           | [![npm](https://img.shields.io/npm/v/@0x/contracts-erc20.svg)](https://www.npmjs.com/package/@0x/contracts-erc20)           | Implementations of various ERC20 tokens                              |
+| [`@0x/contracts-test-utils`](/contracts/test-utils) | [![npm](https://img.shields.io/npm/v/@0x/contracts-test-utils.svg)](https://www.npmjs.com/package/@0x/contracts-test-utils) | TypeScript/Javascript shared utilities used for testing contracts    |
+| [`@0x/contracts-utils`](/contracts/utils)           | [![npm](https://img.shields.io/npm/v/@0x/contracts-utils.svg)](https://www.npmjs.com/package/@0x/contracts-utils)           | Generic libraries and utilities used throughout all of the contracts |
+
+### TypeScript/Javascript Packages

 #### 0x-specific packages

-| Package                                                  | Version                                                                                                                 | Description                                                                                       |
-| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
-| [`0x.js`](/packages/0x.js)                               | [![npm](https://img.shields.io/npm/v/0x.js.svg)](https://www.npmjs.com/package/0x.js)                                   | An aggregate package combining many smaller utility packages for interacting with the 0x protocol |
-| [`@0x/contract-addresses`](/packages/contract-addresses) | [![npm](https://img.shields.io/npm/v/@0x/contract-addresses.svg)](https://www.npmjs.com/package/@0x/contract-addresses) | A tiny utility library for getting known deployed contract addresses for a particular network.    |
-| [`@0x/contract-wrappers`](/packages/contract-wrappers)   | [![npm](https://img.shields.io/npm/v/@0x/contract-wrappers.svg)](https://www.npmjs.com/package/@0x/contract-wrappers)   | JS/TS wrappers for interacting with the 0x smart contracts                                        |
-| [`@0x/order-utils`](/packages/order-utils)               | [![npm](https://img.shields.io/npm/v/@0x/order-utils.svg)](https://www.npmjs.com/package/@0x/order-utils)               | A set of utilities for generating, parsing, signing and validating 0x orders                      |
-| [`@0x/json-schemas`](/packages/json-schemas)             | [![npm](https://img.shields.io/npm/v/@0x/json-schemas.svg)](https://www.npmjs.com/package/@0x/json-schemas)             | 0x-related JSON schemas                                                                           |
-| [`@0x/order-watcher`](/packages/order-watcher)           | [![npm](https://img.shields.io/npm/v/@0x/order-watcher.svg)](https://www.npmjs.com/package/@0x/order-watcher)           | An order watcher daemon that watches for order validity                                           |
-| [`@0x/migrations`](/packages/migrations)                 | [![npm](https://img.shields.io/npm/v/@0x/migrations.svg)](https://www.npmjs.com/package/@0x/migrations)                 | Migration tool for deploying 0x smart contracts on private testnets                               |
-| [`@0x/contract-artifacts`](/packages/contract-artifacts) | [![npm](https://img.shields.io/npm/v/@0x/contract-artifacts.svg)](https://www.npmjs.com/package/@0x/contract-artifacts) | 0x smart contract compilation artifacts                                                           |
-| [`@0x/abi-gen-wrappers`](/packages/abi-gen-wrappers)     | [![npm](https://img.shields.io/npm/v/@0x/abi-gen-wrappers.svg)](https://www.npmjs.com/package/@0x/abi-gen-wrappers)     | Low-level 0x smart contract wrappers generated using `@0x/abi-gen`                                |
-| [`@0x/sra-spec`](/packages/sra-spec)                     | [![npm](https://img.shields.io/npm/v/@0x/sra-spec.svg)](https://www.npmjs.com/package/@0x/sra-spec)                     | OpenAPI specification for the Standard Relayer API                                                |
-| [`@0x/connect`](/packages/connect)                       | [![npm](https://img.shields.io/npm/v/@0x/connect.svg)](https://www.npmjs.com/package/@0x/connect)                       | An HTTP/WS client for interacting with the Standard Relayer API                                   |
-| [`@0x/asset-buyer`](/packages/asset-buyer)               | [![npm](https://img.shields.io/npm/v/@0x/asset-buyer.svg)](https://www.npmjs.com/package/@0x/asset-buyer)               | Convenience package for discovering and buying assets with Ether                                  |
-
-#### Ethereum tooling
-
-| Package                                      | Version                                                                                                     | Description                                                                                                                                                                             |
-| -------------------------------------------- | ----------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| [`@0x/web3-wrapper`](/packages/web3-wrapper) | [![npm](https://img.shields.io/npm/v/@0x/web3-wrapper.svg)](https://www.npmjs.com/package/@0x/web3-wrapper) | An Ethereum JSON RPC client                                                                                                                                                             |
-| [`@0x/sol-compiler`](/packages/sol-compiler) | [![npm](https://img.shields.io/npm/v/@0x/sol-compiler.svg)](https://www.npmjs.com/package/@0x/sol-compiler) | A wrapper around solc-js that adds smart re-compilation, ability to compile an entire project, Solidity version specific compilation, standard input description support and much more. |
-| [`@0x/sol-coverage`](/packages/sol-coverage) | [![npm](https://img.shields.io/npm/v/@0x/sol-coverage.svg)](https://www.npmjs.com/package/@0x/sol-coverage) | A solidity test coverage tool                                                                                                                                                           |
-| [`@0x/sol-profiler`](/packages/sol-profiler) | [![npm](https://img.shields.io/npm/v/@0x/sol-profiler.svg)](https://www.npmjs.com/package/@0x/sol-profiler) | A solidity gas cost profiler                                                                                                                                                            |
-| [`@0x/sol-trace`](/packages/sol-trace)       | [![npm](https://img.shields.io/npm/v/@0x/sol-trace.svg)](https://www.npmjs.com/package/@0x/sol-trace)       | A solidity stack trace tool                                                                                                                                                             |
-| [`@0x/sol-resolver`](/packages/sol-resolver) | [![npm](https://img.shields.io/npm/v/@0x/sol-resolver.svg)](https://www.npmjs.com/package/@0x/sol-resolver) | Import resolver for smart contracts dependencies                                                                                                                                        |
-| [`@0x/subproviders`](/packages/subproviders) | [![npm](https://img.shields.io/npm/v/@0x/subproviders.svg)](https://www.npmjs.com/package/@0x/subproviders) | Web3 provider middlewares (e.g. LedgerSubprovider)                                                                                                                                      |
-| [`@0x/sol-doc`](/packages/sol-doc)           | [![npm](https://img.shields.io/npm/v/@0x/sol-doc.svg)](https://www.npmjs.com/package/@0x/sol-doc)           | Solidity documentation generator                                                                                                                                                        |
-
-#### Utilities
-
-| Package                                                  | Version                                                                                                                 | Description                                                                  |
-| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------- |
-| [`@0x/abi-gen`](/packages/abi-gen)                       | [![npm](https://img.shields.io/npm/v/@0x/abi-gen.svg)](https://www.npmjs.com/package/@0x/abi-gen)                       | Tool to generate TS wrappers from smart contract ABIs                        |
-| [`@0x/tslint-config`](/packages/tslint-config)           | [![npm](https://img.shields.io/npm/v/@0x/tslint-config.svg)](https://www.npmjs.com/package/@0x/tslint-config)           | Custom TSLint rules used by the 0x core team                                 |
-| [`@0x/types`](/packages/types)                           | [![npm](https://img.shields.io/npm/v/@0x/types.svg)](https://www.npmjs.com/package/@0x/types)                           | Shared type declarations                                                     |
-| [`@0x/typescript-typings`](/packages/typescript-typings) | [![npm](https://img.shields.io/npm/v/@0x/typescript-typings.svg)](https://www.npmjs.com/package/@0x/typescript-typings) | Repository of types for external packages                                    |
-| [`@0x/utils`](/packages/utils)                           | [![npm](https://img.shields.io/npm/v/@0x/utils.svg)](https://www.npmjs.com/package/@0x/utils)                           | Shared utilities                                                             |
-| [`@0x/react-docs`](/packages/react-docs)                 | [![npm](https://img.shields.io/npm/v/@0x/react-docs.svg)](https://www.npmjs.com/package/@0x/react-docs)                 | React documentation component for rendering TypeDoc & sol-doc generated JSON |
-| [`@0x/react-shared`](/packages/react-shared)             | [![npm](https://img.shields.io/npm/v/@0x/react-shared.svg)](https://www.npmjs.com/package/@0x/react-shared)             | 0x shared react components                                                   |
-| [`@0x/assert`](/packages/assert)                         | [![npm](https://img.shields.io/npm/v/@0x/assert.svg)](https://www.npmjs.com/package/@0x/assert)                         | Type and schema assertions used by our packages                              |
-| [`@0x/base-contract`](/packages/base-contract)           | [![npm](https://img.shields.io/npm/v/@0x/base-contract.svg)](https://www.npmjs.com/package/@0x/base-contract)           | BaseContract used by auto-generated `abi-gen` wrapper contracts              |
-| [`@0x/dev-utils`](/packages/dev-utils)                   | [![npm](https://img.shields.io/npm/v/@0x/dev-utils.svg)](https://www.npmjs.com/package/@0x/dev-utils)                   | Dev utils to be shared across 0x packages                                    |
-| [`@0x/fill-scenarios`](/packages/fill-scenarios)         | [![npm](https://img.shields.io/npm/v/@0x/fill-scenarios.svg)](https://www.npmjs.com/package/@0x/fill-scenarios)         | 0x order fill scenario generator                                             |
-
-#### Private Packages
-
-| Package                                            | Description                                                                      |
-| -------------------------------------------------- | -------------------------------------------------------------------------------- |
-| [`@0x/contracts`](/contracts/core)                 | 0x protocol solidity smart contracts & tests                                     |
-| [`@0x/instant`](/packages/instant)                 | A free and flexible way to offer simple crypto purchasing in any app or website. |
-| [`@0x/testnet-faucets`](/packages/testnet-faucets) | A faucet micro-service that dispenses test ERC20 tokens or Ether                 |
-| [`@0x/website`](/packages/website)                 | 0x website                                                                       |
+| Package                                                  | Version                                                                                                                 | Description                                                                                    |
+| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
+| [`@0x/protocol-utils`](/packages/protocol-utils)         | [![npm](https://img.shields.io/npm/v/@0x/protocol-utils.svg)](https://www.npmjs.com/package/@0x/protocol-utils)         | A set of utilities for generating, parsing, signing and validating 0x orders                   |
+| [`@0x/contract-addresses`](/packages/contract-addresses) | [![npm](https://img.shields.io/npm/v/@0x/contract-addresses.svg)](https://www.npmjs.com/package/@0x/contract-addresses) | A tiny utility library for getting known deployed contract addresses for a particular network. |
+| [`@0x/contract-wrappers`](/packages/contract-wrappers)   | [![npm](https://img.shields.io/npm/v/@0x/contract-wrappers.svg)](https://www.npmjs.com/package/@0x/contract-wrappers)   | JS/TS wrappers for interacting with the 0x smart contracts                                     |
+| [`@0x/contract-artifacts`](/packages/contract-artifacts) | [![npm](https://img.shields.io/npm/v/@0x/contract-artifacts.svg)](https://www.npmjs.com/package/@0x/contract-artifacts) | 0x smart contract compilation artifacts                                                        |  |

 ## Usage

-Node version >= 6.12 is required.
+Node version 6.x or 8.x is required.

 Most of the packages require additional typings for external dependencies.
 You can include those by prepending the `@0x/typescript-typings` package to your [`typeRoots`](http://www.typescriptlang.org/docs/handbook/tsconfig-json.html) config.
@@ -104,7 +53,7 @@ You can include those by prepending the `@0x/typescript-typings` package to your

 We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.

-#### Read our [contribution guidelines](./CONTRIBUTING.md).
+#### Read our [contribution guidelines](.github/CONTRIBUTING.md).

 ### Install dependencies

@@ -131,7 +80,13 @@ yarn build
 To build a specific package:

 ```bash
-PKG=@0x/web3-wrapper yarn build
+PKG=@0x/protocol-utils yarn build
+```
+
+To build all contracts packages:
+
+```bash
+yarn build:contracts
 ```

 ### Watch
@@ -148,7 +103,7 @@ To watch a specific package and all it's dependent packages:
 PKG=[NPM_PACKAGE_NAME] yarn watch

 e.g
-PKG=@0x/web3-wrapper yarn watch
+PKG=@0x/protocol-utils yarn watch
 ```

 ### Clean
@@ -162,7 +117,7 @@ yarn clean
 Clean a specific package

 ```bash
-PKG=0x.js yarn clean
+PKG=@0x/protocol-utils yarn clean
 ```

 ### Rebuild
@@ -176,7 +131,7 @@ yarn rebuild
 To re-build (clean & build) a specific package & it's deps:

 ```bash
-PKG=0x.js yarn rebuild
+PKG=@0x/protocol-utils yarn rebuild
 ```

 ### Lint
@@ -190,7 +145,7 @@ yarn lint
 Lint a specific package:

 ```bash
-PKG=0x.js yarn lint
+PKG=@0x/protocol-utils yarn lint
 ```

 ### Run Tests
@@ -204,5 +159,11 @@ yarn test
 Run a specific package's test:

 ```bash
-PKG=@0x/web3-wrapper yarn test
+PKG=@0x/protocol-utils yarn test
+```
+
+Run all contracts packages tests:
+
+```bash
+yarn test:contracts
 ```
--- a/contracts/.solhint.json
+++ b/contracts/.solhint.json
@@ -1,21 +0,0 @@
-{
-    "extends": "default",
-    "rules": {
-        "avoid-low-level-calls": false,
-        "avoid-tx-origin": "warn",
-        "bracket-align": false,
-        "code-complexity": false,
-        "compiler-fixed": false,
-        "const-name-snakecase": "error",
-        "expression-indent": "error",
-        "function-max-lines": false,
-        "func-order": "error",
-        "indent": ["error", 4],
-        "max-line-length": ["warn", 160],
-        "no-inline-assembly": false,
-        "quotes": ["error", "double"],
-        "separate-by-one-line-in-contract": "error",
-        "space-after-comma": "error",
-        "statement-indent": "error"
-    }
-}
--- a/contracts/README.md
+++ b/contracts/README.md
@@ -0,0 +1,3 @@
+#### Development
+
+Building solidity files will update the contract artifact in `{package-name}/generated-artifacts/{contract}.json`, but does not automatically update the `contract-artifacts` or `contract-wrappers` packages, which are generated from the artifact JSON. See `contract-artifacts/README.md` for instructions on updating these packages.
--- a/contracts/TESTING.md
+++ b/contracts/TESTING.md
@@ -1,48 +0,0 @@
-# Contracts testing options
-
-## Revert stack traces
-
-If you want to see helpful stack traces (incl. line number, code snippet) for smart contract reverts, run the tests with:
-
-```
-yarn test:trace
-```
-
-**Note:** This currently slows down the test runs and is therefore not enabled by default.
-
-## Backing Ethereum node
-
-By default, our tests run against an in-process [Ganache](https://github.com/trufflesuite/ganache-core) instance. In order to run the tests against [Geth](https://github.com/ethereum/go-ethereum), first follow the instructions in the README for the devnet package to start the devnet Geth node. Then run:
-
-```bash
-TEST_PROVIDER=geth yarn test
-```
-
-## Code coverage
-
-In order to see the Solidity code coverage output generated by `@0x/sol-coverage`, run:
-
-```
-yarn test:coverage
-```
-
-## Gas profiler
-
-In order to profile the gas costs for a specific smart contract call/transaction, you can run the tests in `profiler` mode.
-
-**Note:** Traces emitted by ganache have incorrect gas costs so we recommend using Geth for profiling.
-
-```
-TEST_PROVIDER=geth yarn test:profiler
-```
-
-You'll see a warning that you need to explicitly enable and disable the profiler before and after the block of code you want to profile.
-
-```typescript
-import { profiler } from './utils/profiler';
-profiler.start();
-// Some call to a smart contract
-profiler.stop();
-```
-
-Without explicitly starting and stopping the profiler, the profiler output will be too busy, and therefore unusable.
--- a/contracts/erc20/.npmignore
+++ b/contracts/erc20/.npmignore
@@ -0,0 +1,10 @@
+# Blacklist all files
+.*
+*
+# Whitelist lib
+!lib/**/*
+# Whitelist Solidity contracts
+!contracts/src/**/*
+# Blacklist tests in lib
+/lib/test/*
+# Package specific ignore
--- a/contracts/erc20/CHANGELOG.json
+++ b/contracts/erc20/CHANGELOG.json
--- a/contracts/erc20/CHANGELOG.md
+++ b/contracts/erc20/CHANGELOG.md
@@ -0,0 +1,487 @@
+<!--
+changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
+Edit the package's CHANGELOG.json file only.
+-->
+
+CHANGELOG
+
+## v4.0.0 - _February 16, 2023_
+
+    * Migrated package to foundry
+
+## v3.3.57 - _February 1, 2023_
+
+    * Dependencies updated
+
+## v3.3.56 - _January 30, 2023_
+
+    * Dependencies updated
+
+## v3.3.55 - _January 23, 2023_
+
+    * Dependencies updated
+
+## v3.3.54 - _December 12, 2022_
+
+    * Dependencies updated
+
+## v3.3.53 - _November 23, 2022_
+
+    * Dependencies updated
+
+## v3.3.52 - _November 15, 2022_
+
+    * Dependencies updated
+
+## v3.3.51 - _November 5, 2022_
+
+    * Dependencies updated
+
+## v3.3.50 - _November 2, 2022_
+
+    * Dependencies updated
+
+## v3.3.49 - _October 24, 2022_
+
+    * Dependencies updated
+
+## v3.3.48 - _October 21, 2022_
+
+    * Dependencies updated
+
+## v3.3.47 - _October 13, 2022_
+
+    * Dependencies updated
+
+## v3.3.46 - _October 11, 2022_
+
+    * Dependencies updated
+
+## v3.3.45 - _October 5, 2022_
+
+    * Migrate from TSLint to ESLint and fix linting errors (#589)
+
+## v3.3.44 - _September 21, 2022_
+
+    * Dependencies updated
+
+## v3.3.43 - _September 12, 2022_
+
+    * Dependencies updated
+
+## v3.3.42 - _September 7, 2022_
+
+    * Dependencies updated
+
+## v3.3.41 - _September 2, 2022_
+
+    * Dependencies updated
+
+## v3.3.40 - _September 1, 2022_
+
+    * Dependencies updated
+
+## v3.3.39 - _August 25, 2022_
+
+    * Dependencies updated
+
+## v3.3.38 - _August 25, 2022_
+
+    * Dependencies updated
+
+## v3.3.37 - _August 22, 2022_
+
+    * Dependencies updated
+
+## v3.3.36 - _August 10, 2022_
+
+    * Dependencies updated
+
+## v3.3.35 - _August 9, 2022_
+
+    * Dependencies updated
+
+## v3.3.34 - _August 6, 2022_
+
+    * Dependencies updated
+
+## v3.3.33 - _July 27, 2022_
+
+    * Dependencies updated
+
+## v3.3.32 - _June 14, 2022_
+
+    * Dependencies updated
+
+## v3.3.31 - _June 3, 2022_
+
+    * Dependencies updated
+
+## v3.3.30 - _May 19, 2022_
+
+    * Dependencies updated
+
+## v3.3.29 - _April 22, 2022_
+
+    * Dependencies updated
+
+## v3.3.28 - _March 31, 2022_
+
+    * Dependencies updated
+
+## v3.3.27 - _March 2, 2022_
+
+    * Dependencies updated
+
+## v3.3.26 - _February 22, 2022_
+
+    * Dependencies updated
+
+## v3.3.25 - _December 24, 2021_
+
+    * Dependencies updated
+
+## v3.3.24 - _December 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.23 - _November 16, 2021_
+
+    * Dependencies updated
+
+## v3.3.22 - _November 3, 2021_
+
+    * Dependencies updated
+
+## v3.3.21 - _October 19, 2021_
+
+    * Dependencies updated
+
+## v3.3.20 - _September 15, 2021_
+
+    * Dependencies updated
+
+## v3.3.19 - _September 8, 2021_
+
+    * Dependencies updated
+
+## v3.3.18 - _September 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.17 - _August 19, 2021_
+
+    * Dependencies updated
+
+## v3.3.16 - _August 16, 2021_
+
+    * Dependencies updated
+
+## v3.3.15 - _August 11, 2021_
+
+    * Add ethers as a dependency (#305)
+
+## v3.3.14 - _August 6, 2021_
+
+    * Dependencies updated
+
+## v3.3.13 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.3.12 - _June 11, 2021_
+
+    * Dependencies updated
+
+## v3.3.11 - _June 2, 2021_
+
+    * Dependencies updated
+
+## v3.3.10 - _May 25, 2021_
+
+    * Dependencies updated
+
+## v3.3.9 - _May 21, 2021_
+
+    * Dependencies updated
+
+## v3.3.8 - _May 5, 2021_
+
+    * Dependencies updated
+
+## v3.3.7 - _April 28, 2021_
+
+    * Dependencies updated
+
+## v3.3.6 - _April 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.5 - _March 17, 2021_
+
+    * Dependencies updated
+
+## v3.3.4 - _February 24, 2021_
+
+    * Dependencies updated
+
+## v3.3.3 - _February 10, 2021_
+
+    * Dependencies updated
+
+## v3.3.2 - _January 26, 2021_
+
+    * Dependencies updated
+
+## v3.3.1 - _January 13, 2021_
+
+    * Dependencies updated
+
+## v3.3.0 - _January 4, 2021_
+
+    * Add SPDX license identifiers to solidity files (#105)
+    * Allow for excess return data in `LibERC20TokenV06` compat* functions (#97)
+
+## v3.2.14 - _December 23, 2020_
+
+    * Dependencies updated
+
+## v3.2.13 - _December 17, 2020_
+
+    * Dependencies updated
+
+## v3.2.12 - _December 9, 2020_
+
+    * Dependencies updated
+
+## v3.2.11 - _December 7, 2020_
+
+    * Dependencies updated
+
+## v3.2.10 - _December 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.9 - _November 19, 2020_
+
+    * Dependencies updated
+
+## v3.2.8 - _November 13, 2020_
+
+    * Dependencies updated
+
+## v3.2.7 - _November 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.6 - _November 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.5 - _November 2, 2020_
+
+    * Dependencies updated
+
+## v3.2.4 - _October 28, 2020_
+
+    * Dependencies updated
+
+## v3.2.3 - _October 27, 2020_
+
+    * Dependencies updated
+
+## v3.2.2 - _October 21, 2020_
+
+    * Dependencies updated
+
+## v3.2.1 - _July 15, 2020_
+
+    * Dependencies updated
+
+## v3.2.0 - _June 24, 2020_
+
+    * Add `LibERC20Token.approveIfBelow()` (#2512)
+    * Add solidity 0.6 contracts (#2545)
+    * Update `LibERC20TokenV06` comments. (#2597)
+
+## v3.1.5 - _March 3, 2020_
+
+    * Dependencies updated
+
+## v3.1.4 - _February 27, 2020_
+
+    * Dependencies updated
+
+## v3.1.3 - _February 26, 2020_
+
+    * Dependencies updated
+
+## v3.1.2 - _February 25, 2020_
+
+    * Dependencies updated
+
+## v3.1.1 - _February 15, 2020_
+
+    * Dependencies updated
+
+## v3.1.0 - _February 8, 2020_
+
+    * Add `allowance()` and `balanceOf()` to `LibERC20Token` (#2464)
+    * Fix broken tests (#2456)
+
+## v3.0.6 - _February 6, 2020_
+
+    * Dependencies updated
+
+## v3.0.5 - _February 4, 2020_
+
+    * Dependencies updated
+
+## v3.0.4 - _January 22, 2020_
+
+    * Dependencies updated
+
+## v3.0.3 - _January 6, 2020_
+
+    * Dependencies updated
+
+## v3.0.2 - _December 17, 2019_
+
+    * Dependencies updated
+
+## v3.0.1 - _December 9, 2019_
+
+    * Dependencies updated
+
+## v3.0.0 - _December 2, 2019_
+
+    * Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils (#2330)
+    * Add `decimals()` to `LibERC20Token`. (#2344)
+    * Create `LibERC20Token` (#2309)
+    * Replaced `SafeMath` with `LibSafeMath` (#2254)
+
+## v2.3.0-beta.4 - _December 2, 2019_
+
+    * Dependencies updated
+
+## v2.3.0-beta.3 - _November 20, 2019_
+
+    * Dependencies updated
+
+## v2.3.0-beta.2 - _November 17, 2019_
+
+    * Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils (#2330)
+    * Add `decimals()` to `LibERC20Token`. (#2344)
+
+## v2.3.0-beta.1 - _November 7, 2019_
+
+    * Create `LibERC20Token` (#2309)
+
+## v2.3.0-beta.0 - _October 3, 2019_
+
+    * Dependencies updated
+    * Replaced `SafeMath` with `LibSafeMath` (#2254)
+
+## v2.2.14 - _September 17, 2019_
+
+    * Dependencies updated
+
+## v2.2.13 - _September 3, 2019_
+
+    * Dependencies updated
+
+## v2.2.12 - _August 22, 2019_
+
+    * Dependencies updated
+
+## v2.2.11 - _August 8, 2019_
+
+    * Dependencies updated
+
+## v2.2.10 - _July 31, 2019_
+
+    * Updated calls to <contract wrapper>.deployFrom0xArtifactAsync to include artifact dependencies. (#1995)
+
+## v2.2.9 - _July 24, 2019_
+
+    * Dependencies updated
+
+## v2.2.8 - _July 15, 2019_
+
+    * Dependencies updated
+
+## v2.2.7 - _July 13, 2019_
+
+    * Dependencies updated
+
+## v2.2.6 - _July 13, 2019_
+
+    * Dependencies updated
+
+## v2.2.5 - _May 24, 2019_
+
+    * Dependencies updated
+
+## v2.2.4 - _May 15, 2019_
+
+    * Dependencies updated
+
+## v2.2.3 - _May 14, 2019_
+
+    * Dependencies updated
+
+## v2.2.1 - _May 10, 2019_
+
+    * Dependencies updated
+
+## v2.2.0 - _April 11, 2019_
+
+    * Added UntransferrableDummyERC20Token (#1714)
+
+## v2.1.0 - _March 21, 2019_
+
+    * Run Web3ProviderEngine without excess block polling (#1695)
+
+## v2.0.0 - _March 20, 2019_
+
+    * Upgrade contracts to Solidity 0.5.5 (#1682)
+
+## v1.0.9 - _March 1, 2019_
+
+    * Dependencies updated
+
+## v1.0.8 - _February 27, 2019_
+
+    * Dependencies updated
+
+## v1.0.7 - _February 26, 2019_
+
+    * Dependencies updated
+
+## v1.0.6 - _February 25, 2019_
+
+    * Dependencies updated
+
+## v1.0.5 - _February 9, 2019_
+
+    * Dependencies updated
+
+## v1.0.4 - _February 7, 2019_
+
+    * Dependencies updated
+
+## v1.0.3 - _February 7, 2019_
+
+    * Fake publish to enable pinning
+
+## v1.0.2 - _February 6, 2019_
+
+    * Dependencies updated
+
+## v1.0.1 - _February 5, 2019_
+
+    * Dependencies updated
+
+## v1.0.0 - _Invalid date_
+
+    * Move all ERC20 contracts out of contracts-tokens to new package (#1539)
--- a/contracts/erc20/DEPLOYS.json
+++ b/contracts/erc20/DEPLOYS.json
@@ -0,0 +1,17 @@
+[
+    {
+        "name": "ZRXToken",
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "protocol v1 deploy",
+                "networks": {
+                    "1": "0xe41d2489571d322189246dafa5ebde1f4699f498",
+                    "3": "0xff67881f8d12f372d91baae9752eb3631ff0ed00",
+                    "4": "0x2727e688b8fd40b198cd5fe6e408e00494a06f07",
+                    "42": "0x2002d3812f58e35f0ea1ffbf80a75a38c32175fa"
+                }
+            }
+        ]
+    }
+]
--- a/contracts/erc20/README.md
+++ b/contracts/erc20/README.md
@@ -0,0 +1,69 @@
+## ERC20 Tokens
+
+This package contains implementations of various [ERC20](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md) tokens, including WETH (Wrapped Ether) and ZRX. Addresses of the deployed contracts can be found in this 0x [guide](https://0x.org/docs/guides/0x-cheat-sheet) or the [DEPLOYS](./DEPLOYS.json) file within this package.
+
+## Installation
+
+**Install**
+
+```bash
+npm install @0x/contracts-erc20 --save
+```
+
+## Bug bounty
+
+A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0x.org/docs/guides/bug-bounty-program).
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
+
+Please read our [contribution guidelines](../../.github/CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+
+```bash
+yarn install
+```
+
+### Build
+
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
+
+```bash
+PKG=@0x/contracts-erc20 yarn build
+```
+
+Or continuously rebuild on change:
+
+```bash
+PKG=@0x/contracts-erc20 yarn watch
+```
+
+### Clean
+
+```bash
+yarn clean
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
--- a/contracts/erc20/foundry.toml
+++ b/contracts/erc20/foundry.toml
@@ -0,0 +1,18 @@
+[profile.default]
+src = 'src'
+out = 'out'
+libs = [
+    'lib',
+    'node_modules',
+]
+remappings = [
+    '@0x/contracts-utils/=../utils/'
+]
+allow_paths = [
+    '../utils/'
+]
+
+fs_permissions = [{ access = "read", path = "./out/ZRXToken.sol" }]
+
+optimizer_runs = 1_000_000
+# See more config options https://github.com/foundry-rs/foundry/tree/master/config
--- a/contracts/erc20/lib/forge-std
+++ b/contracts/erc20/lib/forge-std
--- a/contracts/erc20/package.json
+++ b/contracts/erc20/package.json
@@ -0,0 +1,36 @@
+{
+    "name": "@0x/contracts-erc20",
+    "version": "4.0.0",
+    "engines": {
+        "node": ">=6.12"
+    },
+    "description": "Token contracts used by 0x protocol",
+    "main": "lib/src/index.js",
+    "directories": {
+        "test": "test"
+    },
+    "scripts": {
+        "test:ci": "forge test",
+        "docs:md": "ts-doc-gen --sourceDir='$PROJECT_FILES' --output=$MD_FILE_DIR --fileExtension=mdx --tsconfig=./typedoc-tsconfig.json",
+        "docs:json": "typedoc --excludePrivate --excludeExternals --excludeProtected --ignoreCompilerErrors --target ES5 --tsconfig typedoc-tsconfig.json --json $JSON_FILE_PATH $PROJECT_FILES"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/0xProject/protocol.git"
+    },
+    "license": "Apache-2.0",
+    "bugs": {
+        "url": "https://github.com/0xProject/protocol/issues"
+    },
+    "homepage": "https://github.com/0xProject/protocol",
+    "devDependencies": {
+        "@0x/contracts-utils": "^4.8.38",
+        "@0x/ts-doc-gen": "^0.0.28",
+        "typedoc": "~0.16.11"
+    },
+    "dependencies": {},
+    "publishConfig": {
+        "access": "public"
+    },
+    "gitHead": "4f91bfd907996b2f4dd383778b50c479c2602b56"
+}
--- a/contracts/erc20/src/IERC20Token.sol
+++ b/contracts/erc20/src/IERC20Token.sol
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2023 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity >=0.6.5 <0.9;
+
+interface IERC20Token {
+    event Transfer(address indexed from, address indexed to, uint256 value);
+
+    event Approval(address indexed owner, address indexed spender, uint256 value);
+
+    /// @dev send `value` token to `to` from `msg.sender`
+    /// @param to The address of the recipient
+    /// @param value The amount of token to be transferred
+    /// @return True if transfer was successful
+    function transfer(address to, uint256 value) external returns (bool);
+
+    /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
+    /// @param from The address of the sender
+    /// @param to The address of the recipient
+    /// @param value The amount of token to be transferred
+    /// @return True if transfer was successful
+    function transferFrom(address from, address to, uint256 value) external returns (bool);
+
+    /// @dev `msg.sender` approves `spender` to spend `value` tokens
+    /// @param spender The address of the account able to transfer the tokens
+    /// @param value The amount of wei to be approved for transfer
+    /// @return Always true if the call has enough gas to complete execution
+    function approve(address spender, uint256 value) external returns (bool);
+
+    /// @dev Query total supply of token
+    /// @return Total supply of token
+    function totalSupply() external view returns (uint256);
+
+    /// @dev Get the balance of `owner`.
+    /// @param owner The address from which the balance will be retrieved
+    /// @return Balance of owner
+    function balanceOf(address owner) external view returns (uint256);
+
+    /// @dev Get the allowance for `spender` to spend from `owner`.
+    /// @param owner The address of the account owning tokens
+    /// @param spender The address of the account able to transfer the tokens
+    /// @return Amount of remaining tokens allowed to spent
+    function allowance(address owner, address spender) external view returns (uint256);
+
+    /// @dev Get the number of decimals this token has.
+    function decimals() external view returns (uint8);
+}
--- a/contracts/erc20/src/IEtherToken.sol
+++ b/contracts/erc20/src/IEtherToken.sol
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+
+import "./IERC20Token.sol";
+
+interface IEtherToken is IERC20Token {
+    /// @dev Wrap ether.
+    function deposit() external payable;
+
+    /// @dev Unwrap ether.
+    function withdraw(uint256 amount) external;
+}
--- a/contracts/tokens/contracts/tokens/EtherToken/WETH9.sol
+++ b/contracts/tokens/contracts/tokens/EtherToken/WETH9.sol
@@ -13,58 +13,55 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.

-// solhint-disable
-pragma solidity ^0.4.18;
-
+pragma solidity ^0.5.9;

 contract WETH9 {
-    string public name     = "Wrapped Ether";
-    string public symbol   = "WETH";
-    uint8  public decimals = 18;
+    string public name = "Wrapped Ether";
+    string public symbol = "WETH";
+    uint8 public decimals = 18;

-    event  Approval(address indexed _owner, address indexed _spender, uint _value);
-    event  Transfer(address indexed _from, address indexed _to, uint _value);
-    event  Deposit(address indexed _owner, uint _value);
-    event  Withdrawal(address indexed _owner, uint _value);
+    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+    event Transfer(address indexed _from, address indexed _to, uint256 _value);
+    event Deposit(address indexed _owner, uint256 _value);
+    event Withdrawal(address indexed _owner, uint256 _value);

-    mapping (address => uint)                       public  balanceOf;
-    mapping (address => mapping (address => uint))  public  allowance;
+    mapping(address => uint256) public balanceOf;
+    mapping(address => mapping(address => uint256)) public allowance;

-    function() public payable {
+    function() external payable {
        deposit();
    }
+
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
-        Deposit(msg.sender, msg.value);
+        emit Deposit(msg.sender, msg.value);
    }
-    function withdraw(uint wad) public {
+
+    function withdraw(uint256 wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
-        Withdrawal(msg.sender, wad);
+        emit Withdrawal(msg.sender, wad);
    }

-    function totalSupply() public view returns (uint) {
-        return this.balance;
+    function totalSupply() public view returns (uint256) {
+        return address(this).balance;
    }

-    function approve(address guy, uint wad) public returns (bool) {
+    function approve(address guy, uint256 wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
-        Approval(msg.sender, guy, wad);
+        emit Approval(msg.sender, guy, wad);
        return true;
    }

-    function transfer(address dst, uint wad) public returns (bool) {
+    function transfer(address dst, uint256 wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

-    function transferFrom(address src, address dst, uint wad)
-        public
-        returns (bool)
-    {
+    function transferFrom(address src, address dst, uint256 wad) public returns (bool) {
        require(balanceOf[src] >= wad);

-        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
+        if (src != msg.sender && allowance[src][msg.sender] != uint256(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }
@@ -72,13 +69,12 @@ contract WETH9 {
        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

-        Transfer(src, dst, wad);
+        emit Transfer(src, dst, wad);

        return true;
    }
 }

-
 /*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007
--- a/contracts/erc20/src/ZRXToken.sol
+++ b/contracts/erc20/src/ZRXToken.sol
@@ -0,0 +1,136 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.11;
+
+contract Token {
+    /// @return total amount of tokens
+    function totalSupply() constant returns (uint256 supply) {}
+
+    /// @param _owner The address from which the balance will be retrieved
+    /// @return The balance
+    function balanceOf(address _owner) constant returns (uint256 balance) {}
+
+    /// @notice send `_value` token to `_to` from `msg.sender`
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transfer(address _to, uint256 _value) returns (bool success) {}
+
+    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
+    /// @param _from The address of the sender
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {}
+
+    /// @notice `msg.sender` approves `_addr` to spend `_value` tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @param _value The amount of wei to be approved for transfer
+    /// @return Whether the approval was successful or not
+    function approve(address _spender, uint256 _value) returns (bool success) {}
+
+    /// @param _owner The address of the account owning tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @return Amount of remaining tokens allowed to spent
+    function allowance(address _owner, address _spender) constant returns (uint256 remaining) {}
+
+    event Transfer(address indexed _from, address indexed _to, uint256 _value);
+    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+}
+
+contract ERC20Token is Token {
+    function transfer(address _to, uint256 _value) returns (bool) {
+        //Default assumes totalSupply can't be over max (2^256 - 1).
+        if (balances[msg.sender] >= _value && balances[_to] + _value >= balances[_to]) {
+            balances[msg.sender] -= _value;
+            balances[_to] += _value;
+            Transfer(msg.sender, _to, _value);
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
+        if (
+            balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value >= balances[_to]
+        ) {
+            balances[_to] += _value;
+            balances[_from] -= _value;
+            allowed[_from][msg.sender] -= _value;
+            Transfer(_from, _to, _value);
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    function balanceOf(address _owner) constant returns (uint256) {
+        return balances[_owner];
+    }
+
+    function approve(address _spender, uint256 _value) returns (bool) {
+        allowed[msg.sender][_spender] = _value;
+        Approval(msg.sender, _spender, _value);
+        return true;
+    }
+
+    function allowance(address _owner, address _spender) constant returns (uint256) {
+        return allowed[_owner][_spender];
+    }
+
+    mapping(address => uint256) balances;
+    mapping(address => mapping(address => uint256)) allowed;
+    uint256 public totalSupply;
+}
+
+contract UnlimitedAllowanceToken is ERC20Token {
+    uint256 constant MAX_UINT = 2 ** 256 - 1;
+
+    /// @dev ERC20 transferFrom, modified such that an allowance of MAX_UINT represents an unlimited allowance.
+    /// @param _from Address to transfer from.
+    /// @param _to Address to transfer to.
+    /// @param _value Amount to transfer.
+    /// @return Success of transfer.
+    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
+        uint256 allowance = allowed[_from][msg.sender];
+        if (balances[_from] >= _value && allowance >= _value && balances[_to] + _value >= balances[_to]) {
+            balances[_to] += _value;
+            balances[_from] -= _value;
+            if (allowance < MAX_UINT) {
+                allowed[_from][msg.sender] -= _value;
+            }
+            Transfer(_from, _to, _value);
+            return true;
+        } else {
+            return false;
+        }
+    }
+}
+
+contract ZRXToken is UnlimitedAllowanceToken {
+    uint8 public constant decimals = 18;
+    uint256 public totalSupply = 10 ** 27; // 1 billion tokens, 18 decimal places
+    string public constant name = "0x Protocol Token";
+    string public constant symbol = "ZRX";
+
+    function ZRXToken() public {
+        balances[msg.sender] = totalSupply;
+    }
+}
--- a/contracts/erc20/src/v06/LibERC20TokenV06.sol
+++ b/contracts/erc20/src/v06/LibERC20TokenV06.sol
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+
+import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
+import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
+import "../IERC20Token.sol";
+
+library LibERC20TokenV06 {
+    bytes private constant DECIMALS_CALL_DATA = hex"313ce567";
+
+    /// @dev Calls `IERC20Token(token).approve()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param allowance The allowance to set.
+    function compatApprove(IERC20Token token, address spender, uint256 allowance) internal {
+        bytes memory callData = abi.encodeWithSelector(token.approve.selector, spender, allowance);
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).approve()` and sets the allowance to the
+    ///      maximum if the current approval is not already >= an amount.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param amount The minimum allowance needed.
+    function approveIfBelow(IERC20Token token, address spender, uint256 amount) internal {
+        if (token.allowance(address(this), spender) < amount) {
+            compatApprove(token, spender, uint256(-1));
+        }
+    }
+
+    /// @dev Calls `IERC20Token(token).transfer()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransfer(IERC20Token token, address to, uint256 amount) internal {
+        bytes memory callData = abi.encodeWithSelector(token.transfer.selector, to, amount);
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).transferFrom()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param from The owner of the tokens.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransferFrom(IERC20Token token, address from, address to, uint256 amount) internal {
+        bytes memory callData = abi.encodeWithSelector(token.transferFrom.selector, from, to, amount);
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Retrieves the number of decimals for a token.
+    ///      Returns `18` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @return tokenDecimals The number of decimals places for the token.
+    function compatDecimals(IERC20Token token) internal view returns (uint8 tokenDecimals) {
+        tokenDecimals = 18;
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(DECIMALS_CALL_DATA);
+        if (didSucceed && resultData.length >= 32) {
+            tokenDecimals = uint8(LibBytesV06.readUint256(resultData, 0));
+        }
+    }
+
+    /// @dev Retrieves the allowance for a token, owner, and spender.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @param spender The address the spender.
+    /// @return allowance_ The allowance for a token, owner, and spender.
+    function compatAllowance(
+        IERC20Token token,
+        address owner,
+        address spender
+    ) internal view returns (uint256 allowance_) {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeWithSelector(token.allowance.selector, owner, spender)
+        );
+        if (didSucceed && resultData.length >= 32) {
+            allowance_ = LibBytesV06.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Retrieves the balance for a token owner.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @return balance The token balance of an owner.
+    function compatBalanceOf(IERC20Token token, address owner) internal view returns (uint256 balance) {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeWithSelector(token.balanceOf.selector, owner)
+        );
+        if (didSucceed && resultData.length >= 32) {
+            balance = LibBytesV06.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Executes a call on address `target` with calldata `callData`
+    ///      and asserts that either nothing was returned or a single boolean
+    ///      was returned equal to `true`.
+    /// @param target The call target.
+    /// @param callData The abi-encoded call data.
+    function _callWithOptionalBooleanResult(address target, bytes memory callData) private {
+        (bool didSucceed, bytes memory resultData) = target.call(callData);
+        // Revert if the call reverted.
+        if (!didSucceed) {
+            LibRichErrorsV06.rrevert(resultData);
+        }
+        // If we get back 0 returndata, this may be a non-standard ERC-20 that
+        // does not return a boolean. Check that it at least contains code.
+        if (resultData.length == 0) {
+            uint256 size;
+            assembly {
+                size := extcodesize(target)
+            }
+            require(size > 0, "invalid token address, contains no code");
+            return;
+        }
+        // If we get back at least 32 bytes, we know the target address
+        // contains code, and we assume it is a token that returned a boolean
+        // success value, which must be true.
+        if (resultData.length >= 32) {
+            uint256 result = LibBytesV06.readUint256(resultData, 0);
+            if (result == 1) {
+                return;
+            } else {
+                LibRichErrorsV06.rrevert(resultData);
+            }
+        }
+        // If 0 < returndatasize < 32, the target is a contract, but not a
+        // valid token.
+        LibRichErrorsV06.rrevert(resultData);
+    }
+}
--- a/contracts/erc20/src/v06/WETH9V06.sol
+++ b/contracts/erc20/src/v06/WETH9V06.sol
@@ -0,0 +1,755 @@
+// Copyright (C) 2015, 2016, 2017 Dapphub
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// solhint-disable
+pragma solidity ^0.6.0;
+
+contract WETH9V06 {
+    string public name = "Wrapped Ether";
+    string public symbol = "WETH";
+    uint8 public decimals = 18;
+
+    event Approval(address indexed _owner, address indexed _spender, uint _value);
+    event Transfer(address indexed _from, address indexed _to, uint _value);
+    event Deposit(address indexed _owner, uint _value);
+    event Withdrawal(address indexed _owner, uint _value);
+
+    mapping(address => uint) public balanceOf;
+    mapping(address => mapping(address => uint)) public allowance;
+
+    receive() external payable {
+        deposit();
+    }
+
+    function deposit() public payable {
+        balanceOf[msg.sender] += msg.value;
+        emit Deposit(msg.sender, msg.value);
+    }
+
+    function withdraw(uint wad) public {
+        require(balanceOf[msg.sender] >= wad);
+        balanceOf[msg.sender] -= wad;
+        msg.sender.transfer(wad);
+        emit Withdrawal(msg.sender, wad);
+    }
+
+    function totalSupply() public view returns (uint) {
+        return address(this).balance;
+    }
+
+    function approve(address guy, uint wad) public returns (bool) {
+        allowance[msg.sender][guy] = wad;
+        emit Approval(msg.sender, guy, wad);
+        return true;
+    }
+
+    function transfer(address dst, uint wad) public returns (bool) {
+        return transferFrom(msg.sender, dst, wad);
+    }
+
+    function transferFrom(address src, address dst, uint wad) public returns (bool) {
+        require(balanceOf[src] >= wad);
+
+        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
+            require(allowance[src][msg.sender] >= wad);
+            allowance[src][msg.sender] -= wad;
+        }
+
+        balanceOf[src] -= wad;
+        balanceOf[dst] += wad;
+
+        emit Transfer(src, dst, wad);
+
+        return true;
+    }
+}
+
+/*
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
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+*/
--- a/contracts/erc20/src/v08/LibERC20TokenV08.sol
+++ b/contracts/erc20/src/v08/LibERC20TokenV08.sol
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.8.0;
+
+import "@0x/contracts-utils/contracts/src/v08/errors/LibRichErrorsV08.sol";
+import "@0x/contracts-utils/contracts/src/v08/LibBytesV08.sol";
+import "../IERC20Token.sol";
+
+library LibERC20TokenV08 {
+    bytes private constant DECIMALS_CALL_DATA = hex"313ce567";
+
+    /// @dev Calls `IERC20Token(token).approve()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param allowance The allowance to set.
+    function compatApprove(IERC20Token token, address spender, uint256 allowance) internal {
+        bytes memory callData = abi.encodeCall(token.approve, (spender, allowance));
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).approve()` and sets the allowance to the
+    ///      maximum if the current approval is not already >= an amount.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param amount The minimum allowance needed.
+    function approveIfBelow(IERC20Token token, address spender, uint256 amount) internal {
+        if (token.allowance(address(this), spender) < amount) {
+            compatApprove(token, spender, type(uint256).max);
+        }
+    }
+
+    /// @dev Calls `IERC20Token(token).transfer()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransfer(IERC20Token token, address to, uint256 amount) internal {
+        bytes memory callData = abi.encodeCall(token.transfer, (to, amount));
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).transferFrom()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param from The owner of the tokens.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransferFrom(IERC20Token token, address from, address to, uint256 amount) internal {
+        bytes memory callData = abi.encodeCall(token.transferFrom, (from, to, amount));
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Retrieves the number of decimals for a token.
+    ///      Returns `18` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @return tokenDecimals The number of decimals places for the token.
+    function compatDecimals(IERC20Token token) internal view returns (uint8 tokenDecimals) {
+        tokenDecimals = 18;
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(DECIMALS_CALL_DATA);
+        if (didSucceed && resultData.length >= 32) {
+            tokenDecimals = abi.decode(resultData, (uint8));
+        }
+    }
+
+    /// @dev Retrieves the allowance for a token, owner, and spender.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @param spender The address the spender.
+    /// @return allowance_ The allowance for a token, owner, and spender.
+    function compatAllowance(
+        IERC20Token token,
+        address owner,
+        address spender
+    ) internal view returns (uint256 allowance_) {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeCall(token.allowance, (owner, spender))
+        );
+        if (didSucceed && resultData.length >= 32) {
+            allowance_ = abi.decode(resultData, (uint256));
+        }
+    }
+
+    /// @dev Retrieves the balance for a token owner.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @return balance The token balance of an owner.
+    function compatBalanceOf(IERC20Token token, address owner) internal view returns (uint256 balance) {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeCall(token.balanceOf, (owner))
+        );
+        if (didSucceed && resultData.length >= 32) {
+            balance = abi.decode(resultData, (uint256));
+        }
+    }
+
+    /// @dev Executes a call on address `target` with calldata `callData`
+    ///      and asserts that either nothing was returned or a single boolean
+    ///      was returned equal to `true`.
+    /// @param target The call target.
+    /// @param callData The abi-encoded call data.
+    function _callWithOptionalBooleanResult(address target, bytes memory callData) private {
+        (bool didSucceed, bytes memory resultData) = target.call(callData);
+        // Revert if the call reverted.
+        if (!didSucceed) {
+            LibRichErrorsV08.rrevert(resultData);
+        }
+        // If we get back 0 returndata, this may be a non-standard ERC-20 that
+        // does not return a boolean. Check that it at least contains code.
+        if (resultData.length == 0) {
+            require(target.code.length > 0, "invalid token address, contains no code");
+            return;
+        }
+        // If we get back at least 32 bytes, we know the target address
+        // contains code, and we assume it is a token that returned a boolean
+        // success value, which must be true.
+        if (resultData.length >= 32) {
+            if (!abi.decode(resultData, (bool))) {
+                LibRichErrorsV08.rrevert(resultData);
+            }
+        }
+        // If 0 < returndatasize < 32, the target is a contract, but not a
+        // valid token.
+        LibRichErrorsV08.rrevert(resultData);
+    }
+}
--- a/contracts/erc20/test/WETH9V06Test.t.sol
+++ b/contracts/erc20/test/WETH9V06Test.t.sol
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+  Copyright 2023 ZeroEx Intl.
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+pragma solidity ^0.6.5;
+pragma experimental ABIEncoderV2;
+
+import "forge-std/Test.sol";
+import "../src/v06/WETH9V06.sol";
+
+contract WETH9V06Test is Test {
+    address payable internal owner = payable(vm.addr(1));
+    address payable internal user = payable(vm.addr(2));
+    WETH9V06 internal etherToken;
+
+    function setUp() public {
+        vm.deal(owner, 1e20);
+        vm.deal(user, 1e20);
+
+        etherToken = new WETH9V06();
+    }
+
+    function testShouldRevertIfCallerAttemptsToDepositMoreThanTheirBalance() public {
+        vm.prank(user);
+        vm.expectRevert();
+        etherToken.deposit{value: 1e20 + 1}();
+    }
+
+    function testShouldConvertDepositedETHToWrappedETH() public {
+        vm.prank(user);
+        etherToken.deposit{value: 1e20}();
+        vm.stopPrank();
+
+        assertEq(etherToken.balanceOf(user), 1e20);
+        assertEq(address(etherToken).balance, 1e20);
+    }
+
+    function testShouldRevertIfCallerAttemptsToWithdrawMoreThanTheirBalance() public {
+        vm.prank(user);
+        etherToken.deposit{value: 1e20}();
+
+        vm.expectRevert();
+        etherToken.withdraw(1e20 + 1);
+    }
+
+    function testShouldConvertWithdrawWrappedETHToETH() public {
+        vm.prank(user);
+        etherToken.deposit{value: 1e20}();
+        vm.prank(user);
+        etherToken.withdraw(100);
+        vm.stopPrank();
+
+        assertEq(etherToken.balanceOf(user), 1e20 - 100);
+        assertEq(address(etherToken).balance, 1e20 - 100);
+        assertEq(user.balance, 100);
+    }
+
+    function testShouldConvertSentETHToWrappedETH() public {
+        vm.prank(user);
+        address(etherToken).call{value: 1e20}(new bytes(0));
+        vm.stopPrank();
+
+        assertEq(etherToken.balanceOf(user), 1e20);
+        assertEq(address(etherToken).balance, 1e20);
+    }
+}
--- a/contracts/erc20/test/ZRXTokenTest.t.sol
+++ b/contracts/erc20/test/ZRXTokenTest.t.sol
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+  Copyright 2023 ZeroEx Intl.
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+pragma solidity ^0.8.17;
+
+import "forge-std/Test.sol";
+import "../src/IERC20Token.sol";
+
+contract ZRXTokenTest is Test {
+    address payable internal owner = payable(vm.addr(1));
+    address payable internal user = payable(vm.addr(2));
+    address payable internal anotherUser = payable(vm.addr(3));
+    uint256 internal totalSupply = 1_000_000_000 * 1e18;
+    IERC20Token zrxToken;
+
+    function setUp() public {
+        vm.deal(owner, 1e20);
+        vm.deal(user, 1e20);
+
+        vm.prank(owner);
+        bytes memory _bytecode = vm.getCode("./out/ZRXToken.sol/ZRXToken.json");
+        address _address;
+        assembly {
+            _address := create(0, add(_bytecode, 0x20), mload(_bytecode))
+        }
+        vm.stopPrank();
+        zrxToken = IERC20Token(address(_address));
+    }
+
+    function testShouldHave18Decimals() public {
+        assertEq(zrxToken.decimals(), 18);
+    }
+
+    function testShouldHaveTotalSupplyOf1Billion() public {
+        assertEq(zrxToken.totalSupply(), totalSupply);
+    }
+
+    function testShouldInitializeOwnerBalanceToTotalSupply() public {
+        assertEq(zrxToken.balanceOf(owner), totalSupply);
+    }
+
+    function testShouldTransferBalanceCorrectly() public {
+        vm.prank(owner);
+        zrxToken.transfer(user, 100);
+
+        assertEq(zrxToken.balanceOf(user), 100);
+        assertEq(zrxToken.balanceOf(owner), totalSupply - 100);
+    }
+
+    function testShouldReturnTrueOnAZeroValueTransfer() public {
+        vm.prank(owner);
+        bool success = zrxToken.transfer(user, 0);
+        assertTrue(success);
+    }
+
+    function testShouldReturnTrueOnAZeroValueTransferByUserWithZeroBalance() public {
+        vm.prank(anotherUser);
+        bool success = zrxToken.transfer(user, 0);
+        assertTrue(success);
+    }
+
+    function testShouldReturnFalseIfSenderHasInsufficientBalance() public {
+        vm.prank(owner);
+        zrxToken.approve(user, totalSupply + 1);
+        vm.stopPrank();
+
+        bool success = zrxToken.transferFrom(owner, user, totalSupply + 1);
+        assertEq(success, false);
+    }
+
+    function testShouldReturnFalseIfRecipientHasInsufficientAllowance() public {
+        vm.prank(owner);
+        zrxToken.approve(user, totalSupply - 1);
+        vm.stopPrank();
+
+        bool success = zrxToken.transferFrom(owner, user, totalSupply);
+        assertEq(success, false);
+    }
+
+    function testShouldReturnTrueOnAZeroValueApprovedTransfer() public {
+        vm.prank(user);
+        bool success = zrxToken.transferFrom(owner, user, 0);
+        assertEq(success, true);
+    }
+
+    function testShouldNotModifySenderAllowanceIfSetToUINT256Max() public {
+        vm.prank(owner);
+        zrxToken.approve(user, type(uint256).max);
+        vm.stopPrank();
+
+        zrxToken.transferFrom(owner, user, 100);
+        assertEq(zrxToken.allowance(owner, user), type(uint256).max);
+    }
+
+    function testShouldTransferCorrectlyWhenSufficientAllowance() public {
+        vm.prank(owner);
+        zrxToken.approve(user, 1000 * 1e18);
+        vm.stopPrank();
+
+        vm.prank(user);
+        zrxToken.transferFrom(owner, user, 100 * 1e18);
+        assertEq(zrxToken.allowance(owner, user), 900 * 1e18);
+        assertEq(zrxToken.balanceOf(user), 100 * 1e18);
+        assertEq(zrxToken.balanceOf(owner), totalSupply - 100 * 1e18);
+    }
+}
--- a/contracts/examples/CHANGELOG.json
+++ b/contracts/examples/CHANGELOG.json
@@ -1,38 +0,0 @@
-[
-    {
-        "timestamp": 1547561734,
-        "version": "1.0.5",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1547225310,
-        "version": "1.0.4",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1547040760,
-        "version": "1.0.3",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1544741676,
-        "version": "1.0.2",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    }
-]
--- a/contracts/examples/CHANGELOG.md
+++ b/contracts/examples/CHANGELOG.md
@@ -1,22 +0,0 @@
-<!--
-changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
-Edit the package's CHANGELOG.json file only.
-->
-
-CHANGELOG
-
-## v1.0.5 - _January 15, 2019_
-
-    * Dependencies updated
-
-## v1.0.4 - _January 11, 2019_
-
-    * Dependencies updated
-
-## v1.0.3 - _January 9, 2019_
-
-    * Dependencies updated
-
-## v1.0.2 - _December 13, 2018_
-
-    * Dependencies updated
--- a/contracts/examples/README.md
+++ b/contracts/examples/README.md
@@ -1,56 +0,0 @@
-## Contract examples
-
-Example smart contracts that interact with 0x protocol.
-
-## Usage
-
-Contracts can be found in the [contracts](./contracts) directory.
-This package contains example implementations of contracts that interact with the protocol but are _not_ intended for use in production. Examples include [filter](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#filter-contracts) contracts, a [Wallet](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#wallet) contract, and a [Validator](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#validator) contract, among others.
-
-## Contributing
-
-We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
-
-For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
-
-Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
-
-### Install Dependencies
-
-If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
-
-```bash
-yarn config set workspaces-experimental true
-```
-
-Then install dependencies
-
-```bash
-yarn install
-```
-
-### Build
-
-To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
-
-```bash
-PKG=@0x/contracts-examples yarn build
-```
-
-Or continuously rebuild on change:
-
-```bash
-PKG=@0x/contracts-examples yarn watch
-```
-
-### Clean
-
-```bash
-yarn clean
-```
-
-### Lint
-
-```bash
-yarn lint
-```
--- a/contracts/examples/compiler.json
+++ b/contracts/examples/compiler.json
@@ -1,22 +0,0 @@
-{
-    "artifactsDir": "./generated-artifacts",
-    "contractsDir": "./contracts",
-    "compilerSettings": {
-        "optimizer": {
-            "enabled": true,
-            "runs": 1000000
-        },
-        "outputSelection": {
-            "*": {
-                "*": [
-                    "abi",
-                    "evm.bytecode.object",
-                    "evm.bytecode.sourceMap",
-                    "evm.deployedBytecode.object",
-                    "evm.deployedBytecode.sourceMap"
-                ]
-            }
-        }
-    },
-    "contracts": ["ExchangeWrapper", "Validator", "Wallet", "Whitelist"]
-}
--- a/contracts/examples/contracts/ExchangeWrapper/ExchangeWrapper.sol
+++ b/contracts/examples/contracts/ExchangeWrapper/ExchangeWrapper.sol
@@ -1,100 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-
-
-contract ExchangeWrapper {
-
-    // Exchange contract.
-    // solhint-disable-next-line var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-    }
-
-    /// @dev Cancels all orders created by sender with a salt less than or equal to the targetOrderEpoch
-    ///      and senderAddress equal to this contract.
-    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param makerSignature Proof that maker wishes to call this function with given params.
-    function cancelOrdersUpTo(
-        uint256 targetOrderEpoch,
-        uint256 salt,
-        bytes makerSignature
-    )
-        external
-    {
-        address makerAddress = msg.sender;
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.cancelOrdersUpTo.selector,
-            targetOrderEpoch
-        );
-
-        // Call `cancelOrdersUpTo` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            makerAddress,
-            data,
-            makerSignature
-        );
-    }
-
-    /// @dev Fills an order using `msg.sender` as the taker.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param orderSignature Proof that order has been created by maker.
-    /// @param takerSignature Proof that taker wishes to call this function with given params.
-    function fillOrder(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        uint256 salt,
-        bytes memory orderSignature,
-        bytes memory takerSignature
-    )
-        public
-    {
-        address takerAddress = msg.sender;
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.fillOrder.selector,
-            order,
-            takerAssetFillAmount,
-            orderSignature
-        );
-
-        // Call `fillOrder` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            takerAddress,
-            data,
-            takerSignature
-        );
-    }
-}
--- a/contracts/examples/contracts/Validator/Validator.sol
+++ b/contracts/examples/contracts/Validator/Validator.sol
@@ -1,56 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IValidator.sol";
-
-
-contract Validator is 
-    IValidator
-{
-
-    // The single valid signer for this wallet.
-    // solhint-disable-next-line var-name-mixedcase
-    address internal VALID_SIGNER;
-
-    /// @dev constructs a new `Validator` with a single valid signer.
-    /// @param validSigner The sole, valid signer.
-    constructor (address validSigner) public {
-        VALID_SIGNER = validSigner;
-    }
-
-    /// @dev Verifies that a signature is valid. `signer` must match `VALID_SIGNER`.
-    /// @param hash Message hash that is signed.
-    /// @param signerAddress Address that should have signed the given hash.
-    /// @param signature Proof of signing.
-    /// @return Validity of signature.
-    // solhint-disable no-unused-vars
-    function isValidSignature(
-        bytes32 hash,
-        address signerAddress,
-        bytes signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        return (signerAddress == VALID_SIGNER);
-    }
-    // solhint-enable no-unused-vars
-}
--- a/contracts/examples/contracts/Wallet/Wallet.sol
+++ b/contracts/examples/contracts/Wallet/Wallet.sol
@@ -1,65 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IWallet.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-
-
-contract Wallet is 
-    IWallet
-{
-    using LibBytes for bytes;
-
-    // The owner of this wallet.
-    // solhint-disable-next-line var-name-mixedcase
-    address internal WALLET_OWNER;
-
-    /// @dev constructs a new `Wallet` with a single owner.
-    /// @param walletOwner The owner of this wallet.
-    constructor (address walletOwner) public {
-        WALLET_OWNER = walletOwner;
-    }
-
-    /// @dev Validates an EIP712 signature.
-    ///      The signer must match the owner of this wallet.
-    /// @param hash Message hash that is signed.
-    /// @param eip712Signature Proof of signing.
-    /// @return Validity of signature.
-    function isValidSignature(
-        bytes32 hash,
-        bytes eip712Signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        require(
-            eip712Signature.length == 65,
-            "LENGTH_65_REQUIRED"
-        );
-
-        uint8 v = uint8(eip712Signature[0]);
-        bytes32 r = eip712Signature.readBytes32(1);
-        bytes32 s = eip712Signature.readBytes32(33);
-        address recoveredAddress = ecrecover(hash, v, r, s);
-        isValid = WALLET_OWNER == recoveredAddress;
-        return isValid;
-    }
-}
--- a/contracts/examples/contracts/Whitelist/Whitelist.sol
+++ b/contracts/examples/contracts/Whitelist/Whitelist.sol
@@ -1,136 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-
-
-contract Whitelist is
-    Ownable
-{
-
-    // Mapping of address => whitelist status.
-    mapping (address => bool) public isWhitelisted;
-
-    // Exchange contract.
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    bytes internal TX_ORIGIN_SIGNATURE;
-    // solhint-enable var-name-mixedcase
-
-    byte constant internal VALIDATOR_SIGNATURE_BYTE = "\x05";
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-        TX_ORIGIN_SIGNATURE = abi.encodePacked(address(this), VALIDATOR_SIGNATURE_BYTE);
-    }
-
-    /// @dev Adds or removes an address from the whitelist.
-    /// @param target Address to add or remove from whitelist.
-    /// @param isApproved Whitelist status to assign to address.
-    function updateWhitelistStatus(
-        address target,
-        bool isApproved
-    )
-        external
-        onlyOwner
-    {
-        isWhitelisted[target] = isApproved;
-    }
-
-    /// @dev Verifies signer is same as signer of current Ethereum transaction.
-    ///      NOTE: This function can currently be used to validate signatures coming from outside of this contract.
-    ///      Extra safety checks can be added for a production contract.
-    /// @param signerAddress Address that should have signed the given hash.
-    /// @param signature Proof of signing.
-    /// @return Validity of order signature.
-    // solhint-disable no-unused-vars
-    function isValidSignature(
-        bytes32 hash,
-        address signerAddress,
-        bytes signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        // solhint-disable-next-line avoid-tx-origin
-        return signerAddress == tx.origin;
-    }
-    // solhint-enable no-unused-vars
-
-    /// @dev Fills an order using `msg.sender` as the taker.
-    ///      The transaction will revert if both the maker and taker are not whitelisted.
-    ///      Orders should specify this contract as the `senderAddress` in order to gaurantee
-    ///      that both maker and taker have been whitelisted.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param orderSignature Proof that order has been created by maker.
-    function fillOrderIfWhitelisted(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        uint256 salt,
-        bytes memory orderSignature
-    )
-        public
-    {
-        address takerAddress = msg.sender;
-
-        // This contract must be the entry point for the transaction.
-        require(
-            // solhint-disable-next-line avoid-tx-origin
-            takerAddress == tx.origin,
-            "INVALID_SENDER"
-        );
-
-        // Check if maker is on the whitelist.
-        require(
-            isWhitelisted[order.makerAddress],
-            "MAKER_NOT_WHITELISTED"
-        );
-
-        // Check if taker is on the whitelist.
-        require(
-            isWhitelisted[takerAddress],
-            "TAKER_NOT_WHITELISTED"
-        );
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.fillOrder.selector,
-            order,
-            takerAssetFillAmount,
-            orderSignature
-        );
-
-        // Call `fillOrder` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            takerAddress,
-            data,
-            TX_ORIGIN_SIGNATURE
-        );
-    }
-}
--- a/contracts/examples/package.json
+++ b/contracts/examples/package.json
@@ -1,81 +0,0 @@
-{
-    "name": "@0x/contracts-examples",
-    "version": "1.0.5",
-    "engines": {
-        "node": ">=6.12"
-    },
-    "description": "Smart contract examples of 0x protocol",
-    "main": "lib/src/index.js",
-    "directories": {
-        "test": "test"
-    },
-    "scripts": {
-        "build": "yarn pre_build && tsc -b",
-        "build:ci": "yarn build",
-        "pre_build": "run-s compile generate_contract_wrappers",
-        "compile": "sol-compiler",
-        "watch": "sol-compiler -w",
-        "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
-        "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
-        "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
-        "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
-    },
-    "config": {
-        "abis": "generated-artifacts/@(ExchangeWrapper|Validator|Wallet|Whitelist).json"
-    },
-    "repository": {
-        "type": "git",
-        "url": "https://github.com/0xProject/0x-monorepo.git"
-    },
-    "license": "Apache-2.0",
-    "bugs": {
-        "url": "https://github.com/0xProject/0x-monorepo/issues"
-    },
-    "homepage": "https://github.com/0xProject/0x-monorepo/contracts/examples/README.md",
-    "devDependencies": {
-        "@0x/abi-gen": "^1.0.22",
-        "@0x/contracts-test-utils": "^2.0.0",
-        "@0x/dev-utils": "^1.0.24",
-        "@0x/sol-compiler": "^2.0.2",
-        "@0x/subproviders": "^2.1.11",
-        "@0x/tslint-config": "^2.0.2",
-        "@types/bn.js": "^4.11.0",
-        "@types/lodash": "4.14.104",
-        "@types/node": "*",
-        "@types/yargs": "^10.0.0",
-        "chai": "^4.0.1",
-        "chai-as-promised": "^7.1.0",
-        "chai-bignumber": "^2.0.1",
-        "dirty-chai": "^2.0.1",
-        "ethereumjs-abi": "0.6.5",
-        "make-promises-safe": "^1.1.0",
-        "mocha": "^4.1.0",
-        "npm-run-all": "^4.1.2",
-        "shx": "^0.2.2",
-        "solhint": "^1.4.1",
-        "tslint": "5.11.0",
-        "typescript": "3.0.1",
-        "yargs": "^10.0.3"
-    },
-    "dependencies": {
-        "@0x/base-contract": "^3.0.13",
-        "@0x/contracts-interfaces": "^1.0.5",
-        "@0x/contracts-libs": "^1.0.5",
-        "@0x/contracts-multisig": "^1.0.5",
-        "@0x/contracts-tokens": "^1.0.5",
-        "@0x/contracts-utils": "^1.0.5",
-        "@0x/order-utils": "^3.1.2",
-        "@0x/types": "^1.5.2",
-        "@0x/typescript-typings": "^3.0.8",
-        "@0x/utils": "^3.0.1",
-        "@0x/web3-wrapper": "^3.2.4",
-        "@types/js-combinatorics": "^0.5.29",
-        "bn.js": "^4.11.8",
-        "ethereum-types": "^1.1.6",
-        "ethereumjs-util": "^5.1.1",
-        "lodash": "^4.17.5"
-    },
-    "publishConfig": {
-        "access": "public"
-    }
-}
--- a/contracts/examples/src/artifacts/index.ts
+++ b/contracts/examples/src/artifacts/index.ts
@@ -1,13 +0,0 @@
-import { ContractArtifact } from 'ethereum-types';
-
-import * as ExchangeWrapper from '../../generated-artifacts/ExchangeWrapper.json';
-import * as Validator from '../../generated-artifacts/Validator.json';
-import * as Wallet from '../../generated-artifacts/Wallet.json';
-import * as Whitelist from '../../generated-artifacts/Whitelist.json';
-
-export const artifacts = {
-    ExchangeWrapper: ExchangeWrapper as ContractArtifact,
-    Validator: Validator as ContractArtifact,
-    Wallet: Wallet as ContractArtifact,
-    Whitelist: Whitelist as ContractArtifact,
-};
--- a/contracts/examples/src/index.ts
+++ b/contracts/examples/src/index.ts
@@ -1,2 +0,0 @@
-export * from './artifacts';
-export * from './wrappers';
--- a/contracts/examples/src/wrappers/index.ts
+++ b/contracts/examples/src/wrappers/index.ts
@@ -1,4 +0,0 @@
-export * from '../../generated-wrappers/exchange_wrapper';
-export * from '../../generated-wrappers/validator';
-export * from '../../generated-wrappers/wallet';
-export * from '../../generated-wrappers/whitelist';
--- a/contracts/examples/tsconfig.json
+++ b/contracts/examples/tsconfig.json
@@ -1,16 +0,0 @@
-{
-    "extends": "../../tsconfig",
-    "compilerOptions": {
-        "outDir": "lib",
-        "rootDir": ".",
-        "resolveJsonModule": true
-    },
-    "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
-    "files": [
-        "./generated-artifacts/ExchangeWrapper.json",
-        "./generated-artifacts/Validator.json",
-        "./generated-artifacts/Wallet.json",
-        "./generated-artifacts/Whitelist.json"
-    ],
-    "exclude": ["./deploy/solc/solc_bin"]
-}
--- a/contracts/examples/tslint.json
+++ b/contracts/examples/tslint.json
@@ -1,6 +0,0 @@
-{
-    "extends": ["@0x/tslint-config"],
-    "rules": {
-        "custom-no-magic-numbers": false
-    }
-}
--- a/contracts/extensions/CHANGELOG.json
+++ b/contracts/extensions/CHANGELOG.json
@@ -1,56 +0,0 @@
-[
-    {
-        "timestamp": 1547561734,
-        "version": "1.2.2",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1547225310,
-        "version": "1.2.1",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "version": "1.2.0",
-        "changes": [
-            {
-                "note": "Added Dutch Auction Wrapper",
-                "pr": 1465
-            }
-        ],
-        "timestamp": 1547040760
-    },
-    {
-        "version": "1.1.0",
-        "changes": [
-            {
-                "note": "Added Balance Threshold Filter",
-                "pr": 1383
-            },
-            {
-                "note": "Add OrderMatcher",
-                "pr": 1117
-            },
-            {
-                "note": "Add OrderValidator",
-                "pr": 1464
-            }
-        ]
-    },
-    {
-        "timestamp": 1544741676,
-        "version": "1.0.2",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    }
-]
--- a/contracts/extensions/CHANGELOG.md
+++ b/contracts/extensions/CHANGELOG.md
@@ -1,28 +0,0 @@
-<!--
-changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
-Edit the package's CHANGELOG.json file only.
-->
-
-CHANGELOG
-
-## v1.2.2 - _January 15, 2019_
-
-    * Dependencies updated
-
-## v1.2.1 - _January 11, 2019_
-
-    * Dependencies updated
-
-## v1.2.0 - _January 9, 2019_
-
-    * Added Dutch Auction Wrapper (#1465)
-
-## v1.1.0 - _Invalid date_
-
-    * Added Balance Threshold Filter (#1383)
-    * Add OrderMatcher (#1117)
-    * Add OrderValidator (#1464)
-
-## v1.0.2 - _December 13, 2018_
-
-    * Dependencies updated
--- a/contracts/extensions/DEPLOYS.json
+++ b/contracts/extensions/DEPLOYS.json
@@ -1,31 +0,0 @@
-[
-    {
-        "name": "Forwarder",
-        "version": "1.1.0",
-        "changes": [
-            {
-                "note": "Round up when calculating remaining amounts in marketBuy functions",
-                "pr": 1162,
-                "networks": {
-                    "1": "0x5468a1dc173652ee28d249c271fa9933144746b1",
-                    "3": "0x2240dab907db71e64d3e0dba4800c83b5c502d4e",
-                    "42": "0x17992e4ffb22730138e4b62aaa6367fa9d3699a6"
-                }
-            }
-        ]
-    },
-    {
-        "name": "Forwarder",
-        "version": "1.0.0",
-        "changes": [
-            {
-                "note": "protocol v2 deploy",
-                "networks": {
-                    "1": "0x7afc2d5107af94c462a194d2c21b5bdd238709d6",
-                    "3": "0x3983e204b12b3c02fb0638caf2cd406a62e0ead3",
-                    "42": "0xd85e2fa7e7e252b27b01bf0d65c946959d2f45b8"
-                }
-            }
-        ]
-    }
-]
--- a/contracts/extensions/README.md
+++ b/contracts/extensions/README.md
@@ -1,69 +0,0 @@
-## Contract extensions
-
-Smart contracts that implement extensions for the 0x protocol.
-
-## Usage
-
-Contract extensions of the protocol can be found in the [contracts](./contracts) directory. This directory contains contracts that interact with the 2.0.0 contracts and will be used in production, such as the [Forwarder](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarder-specification.md) contract.
-
-## Bug bounty
-
-A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0xproject.com/wiki#Bug-Bounty).
-
-## Contributing
-
-We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
-
-For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
-
-Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
-
-### Install Dependencies
-
-If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
-
-```bash
-yarn config set workspaces-experimental true
-```
-
-Then install dependencies
-
-```bash
-yarn install
-```
-
-### Build
-
-To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
-
-```bash
-PKG=@0x/contracts-extensions yarn build
-```
-
-Or continuously rebuild on change:
-
-```bash
-PKG=@0x/contracts-extensions yarn watch
-```
-
-### Clean
-
-```bash
-yarn clean
-```
-
-### Lint
-
-```bash
-yarn lint
-```
-
-### Run Tests
-
-```bash
-yarn test
-```
-
-#### Testing options
-
-Contracts testing options like coverage, profiling, revert traces or backing node choosing - are described [here](../TESTING.md).
--- a/contracts/extensions/compiler.json
+++ b/contracts/extensions/compiler.json
@@ -1,22 +0,0 @@
-{
-    "artifactsDir": "./generated-artifacts",
-    "contractsDir": "./contracts",
-    "compilerSettings": {
-        "optimizer": {
-            "enabled": true,
-            "runs": 1000000
-        },
-        "outputSelection": {
-            "*": {
-                "*": [
-                    "abi",
-                    "evm.bytecode.object",
-                    "evm.bytecode.sourceMap",
-                    "evm.deployedBytecode.object",
-                    "evm.deployedBytecode.sourceMap"
-                ]
-            }
-        }
-    },
-    "contracts": ["BalanceThresholdFilter", "DutchAuction", "Forwarder", "OrderMatcher", "OrderValidator"]
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
@@ -1,45 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "./interfaces/IThresholdAsset.sol";
-import "./MixinBalanceThresholdFilterCore.sol";
-
-
-contract BalanceThresholdFilter is
-    MixinBalanceThresholdFilterCore
-{
-
-    /// @dev Constructs BalanceThresholdFilter.
-    /// @param exchange Address of 0x exchange.
-    /// @param thresholdAsset The asset that must be held by makers/takers.
-    /// @param balanceThreshold The minimum balance of `thresholdAsset` that must be held by makers/takers.
-    constructor(
-        address exchange,
-        address thresholdAsset,
-        uint256 balanceThreshold
-    )
-        public
-    {
-        EXCHANGE = IExchange(exchange);
-        THRESHOLD_ASSET = IThresholdAsset(thresholdAsset);
-        BALANCE_THRESHOLD = balanceThreshold;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
@@ -1,135 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-libs/contracts/libs/LibExchangeSelectors.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "./mixins/MBalanceThresholdFilterCore.sol";
-import "./MixinExchangeCalldata.sol";
-
-
-contract MixinBalanceThresholdFilterCore is
-    MBalanceThresholdFilterCore,
-    MixinExchangeCalldata,
-    LibOrder,
-    LibExchangeSelectors
-{
-
-    /// @dev Executes an Exchange transaction iff the maker and taker meet 
-    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
-    ///      the exchange function is a cancellation.
-    ///      Supported Exchange functions:
-    ///          batchFillOrders
-    ///          batchFillOrdersNoThrow
-    ///          batchFillOrKillOrders
-    ///          fillOrder
-    ///          fillOrderNoThrow
-    ///          fillOrKillOrder
-    ///          marketBuyOrders
-    ///          marketBuyOrdersNoThrow
-    ///          marketSellOrders
-    ///          marketSellOrdersNoThrow
-    ///          matchOrders
-    ///          cancelOrder
-    ///          batchCancelOrders
-    ///          cancelOrdersUpTo
-    ///     Trying to call any other exchange function will throw.
-    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
-    /// @param signerAddress Address of transaction signer.
-    /// @param signedExchangeTransaction AbiV2 encoded calldata.
-    /// @param signature Proof of signer transaction by signer.
-    function executeTransaction(
-        uint256 salt,
-        address signerAddress,
-        bytes signedExchangeTransaction,
-        bytes signature
-    ) 
-        external
-    {
-        // Get accounts whose balances must be validated
-        address[] memory addressesToValidate = getAddressesToValidate(signerAddress);
-
-        // Validate account balances
-        uint256 balanceThreshold = BALANCE_THRESHOLD;
-        IThresholdAsset thresholdAsset = THRESHOLD_ASSET;
-        for (uint256 i = 0; i < addressesToValidate.length; ++i) {
-            uint256 addressBalance = thresholdAsset.balanceOf(addressesToValidate[i]);
-            require(
-                addressBalance >= balanceThreshold,
-                "AT_LEAST_ONE_ADDRESS_DOES_NOT_MEET_BALANCE_THRESHOLD"
-            );
-        }
-        emit ValidatedAddresses(addressesToValidate);
-        
-        // All addresses are valid. Execute exchange function.
-        EXCHANGE.executeTransaction(
-            salt,
-            signerAddress,
-            signedExchangeTransaction,
-            signature
-        );
-    }
-
-    /// @dev Constructs an array of addresses to be validated.
-    ///      Addresses depend on which Exchange function is to be called
-    ///      (defined by `signedExchangeTransaction` above).
-    /// @param signerAddress Address of transaction signer.
-    /// @return addressesToValidate Array of addresses to validate.
-    function getAddressesToValidate(address signerAddress)
-        internal pure
-        returns (address[] memory addressesToValidate)
-    {
-        bytes4 exchangeFunctionSelector = bytes4(exchangeCalldataload(0));
-        // solhint-disable expression-indent
-        if (
-            exchangeFunctionSelector == BATCH_FILL_ORDERS_SELECTOR              ||
-            exchangeFunctionSelector == BATCH_FILL_ORDERS_NO_THROW_SELECTOR     ||
-            exchangeFunctionSelector == BATCH_FILL_OR_KILL_ORDERS_SELECTOR      ||
-            exchangeFunctionSelector == MARKET_BUY_ORDERS_SELECTOR              ||
-            exchangeFunctionSelector == MARKET_BUY_ORDERS_NO_THROW_SELECTOR     ||
-            exchangeFunctionSelector == MARKET_SELL_ORDERS_SELECTOR             ||
-            exchangeFunctionSelector == MARKET_SELL_ORDERS_NO_THROW_SELECTOR
-        ) {
-            addressesToValidate = loadMakerAddressesFromOrderArray(0);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (
-            exchangeFunctionSelector == FILL_ORDER_SELECTOR             ||
-            exchangeFunctionSelector == FILL_ORDER_NO_THROW_SELECTOR    ||
-            exchangeFunctionSelector == FILL_OR_KILL_ORDER_SELECTOR
-        ) {
-            address makerAddress = loadMakerAddressFromOrder(0);
-            addressesToValidate = addressesToValidate.append(makerAddress);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (exchangeFunctionSelector == MATCH_ORDERS_SELECTOR) {
-            address leftMakerAddress = loadMakerAddressFromOrder(0);
-            addressesToValidate = addressesToValidate.append(leftMakerAddress);
-            address rightMakerAddress = loadMakerAddressFromOrder(1);
-            addressesToValidate = addressesToValidate.append(rightMakerAddress);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (
-            exchangeFunctionSelector != CANCEL_ORDER_SELECTOR           &&
-            exchangeFunctionSelector != BATCH_CANCEL_ORDERS_SELECTOR    &&
-            exchangeFunctionSelector != CANCEL_ORDERS_UP_TO_SELECTOR
-        ) {
-            revert("INVALID_OR_BLOCKED_EXCHANGE_SELECTOR");
-        }
-        // solhint-enable expression-indent
-        return addressesToValidate;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
@@ -1,103 +0,0 @@
-    
-    /*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "./mixins/MExchangeCalldata.sol";
-import "@0x/contracts-libs/contracts/libs/LibAddressArray.sol";
-
-
-contract MixinExchangeCalldata is 
-    MExchangeCalldata
-{
-
-    using LibAddressArray for address[];
-
-    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
-    ///      which is accessed through `signedExchangeTransaction`.
-    /// @param offset  Offset into the Exchange calldata.
-    /// @return value  Corresponding 32 byte value stored at `offset`.
-    function exchangeCalldataload(uint256 offset)
-        internal pure
-        returns (bytes32 value)
-    {
-        assembly {
-            // Pointer to exchange transaction
-            // 0x04 for calldata selector
-            // 0x40 to access `signedExchangeTransaction`, which is the third parameter
-            let exchangeTxPtr := calldataload(0x44)
-
-            // Offset into Exchange calldata
-            // We compute this by adding 0x24 to the `exchangeTxPtr` computed above.
-            // 0x04 for calldata selector
-            // 0x20 for length field of `signedExchangeTransaction`
-            let exchangeCalldataOffset := add(exchangeTxPtr, add(0x24, offset))
-            value := calldataload(exchangeCalldataOffset)
-        }
-        return value;
-    }
-
-    /// @dev Convenience function that skips the 4 byte selector when loading
-    ///      from the embedded Exchange calldata.
-    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
-    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
-    function loadExchangeData(uint256 offset)
-        internal pure
-        returns (bytes32 value)
-    {
-        value = exchangeCalldataload(offset + 4);
-        return value;
-    }
-
-    /// @dev Extracts the maker address from an order stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
-    /// @return makerAddress The extracted maker address.
-    function loadMakerAddressFromOrder(uint256 orderParamIndex)
-        internal pure
-        returns (address makerAddress)
-    {
-        uint256 orderOffsetInBytes = orderParamIndex * 32;
-        uint256 orderPtr = uint256(loadExchangeData(orderOffsetInBytes));
-        makerAddress = address(loadExchangeData(orderPtr));
-        return makerAddress;
-    }
-
-    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
-    /// @return makerAddresses The extracted maker addresses.
-    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
-        internal pure
-        returns (address[] makerAddresses)
-    {
-        uint256 orderArrayOffsetInBytes = orderArrayParamIndex * 32;
-        uint256 orderArrayPtr = uint256(loadExchangeData(orderArrayOffsetInBytes));
-        uint256 orderArrayLength = uint256(loadExchangeData(orderArrayPtr));
-        uint256 orderArrayLengthInBytes = orderArrayLength * 32;
-        uint256 orderArrayElementPtr = orderArrayPtr + 32;
-        uint256 orderArrayElementEndPtr = orderArrayElementPtr + orderArrayLengthInBytes;
-        for (uint orderPtrOffset = orderArrayElementPtr; orderPtrOffset < orderArrayElementEndPtr; orderPtrOffset += 32) {
-            uint256 orderPtr = uint256(loadExchangeData(orderPtrOffset));
-            address makerAddress = address(loadExchangeData(orderPtr + orderArrayElementPtr));
-            makerAddresses = makerAddresses.append(makerAddress);
-        }
-        return makerAddresses;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
@@ -1,55 +0,0 @@
-
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IBalanceThresholdFilterCore {
-    
-    /// @dev Executes an Exchange transaction iff the maker and taker meet 
-    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
-    ///      the exchange function is a cancellation.
-    ///      Supported Exchange functions:
-    ///         - batchFillOrders
-    ///         - batchFillOrdersNoThrow
-    ///         - batchFillOrKillOrders
-    ///         - fillOrder
-    ///         - fillOrderNoThrow
-    ///         - fillOrKillOrder
-    ///         - marketBuyOrders
-    ///         - marketBuyOrdersNoThrow
-    ///         - marketSellOrders
-    ///         - marketSellOrdersNoThrow
-    ///         - matchOrders
-    ///         - cancelOrder
-    ///         - batchCancelOrders
-    ///         - cancelOrdersUpTo
-    ///     Trying to call any other exchange function will throw.
-    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
-    /// @param signerAddress Address of transaction signer.
-    /// @param signedExchangeTransaction AbiV2 encoded calldata.
-    /// @param signature Proof of signer transaction by signer.
-    function executeTransaction(
-        uint256 salt,
-        address signerAddress,
-        bytes signedExchangeTransaction,
-        bytes signature
-    ) 
-        external;
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
@@ -1,31 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IThresholdAsset {
-
-    /// @param _owner The address from which the balance will be retrieved
-    /// @return Balance of owner
-    function balanceOf(address _owner)
-        external
-        view
-        returns (uint256);
-
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
@@ -1,54 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "../interfaces/IThresholdAsset.sol";
-import "../interfaces/IBalanceThresholdFilterCore.sol";
-
-
-contract MBalanceThresholdFilterCore is
-    IBalanceThresholdFilterCore
-{
-
-    // Points to 0x exchange contract
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    // The asset that must be held by makers/takers
-    IThresholdAsset internal THRESHOLD_ASSET;
-
-    // The minimum balance of `THRESHOLD_ASSET` that must be held by makers/takers
-    uint256 internal BALANCE_THRESHOLD;
-    // solhint-enable var-name-mixedcase
-
-    // Addresses that hold at least `BALANCE_THRESHOLD` of `THRESHOLD_ASSET`
-    event ValidatedAddresses (
-        address[] addresses
-    );
-
-    /// @dev Constructs an array of addresses to be validated.
-    ///      Addresses depend on which Exchange function is to be called
-    ///      (defined by `signedExchangeTransaction` above).
-    /// @param signerAddress Address of transaction signer.
-    /// @return addressesToValidate Array of addresses to validate.
-    function getAddressesToValidate(address signerAddress)
-        internal pure
-        returns (address[] memory addressesToValidate);
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
@@ -1,56 +0,0 @@
-    
-    /*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract MExchangeCalldata {
-
-    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
-    ///      which is accessed through `signedExchangeTransaction`.
-    /// @param offset  Offset into the Exchange calldata.
-    /// @return value  Corresponding 32 byte value stored at `offset`.
-    function exchangeCalldataload(uint256 offset)
-        internal pure
-        returns (bytes32 value);
-
-    /// @dev Convenience function that skips the 4 byte selector when loading
-    ///      from the embedded Exchange calldata.
-    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
-    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
-    function loadExchangeData(uint256 offset)
-        internal pure
-        returns (bytes32 value);
-
-    /// @dev Extracts the maker address from an order stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
-    /// @return makerAddress The extracted maker address.
-    function loadMakerAddressFromOrder(uint256 orderParamIndex)
-        internal pure
-        returns (address makerAddress);
-
-    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
-    /// @return makerAddresses The extracted maker addresses.
-    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
-        internal pure
-        returns (address[] makerAddresses);
-}
--- a/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
+++ b/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
@@ -1,205 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
-
-
-contract DutchAuction is
-    SafeMath
-{
-    using LibBytes for bytes;
-
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    struct AuctionDetails {
-        uint256 beginTimeSeconds;    // Auction begin unix timestamp: sellOrder.makerAssetData
-        uint256 endTimeSeconds;      // Auction end unix timestamp: sellOrder.expiryTimeSeconds
-        uint256 beginAmount;         // Auction begin amount: sellOrder.makerAssetData
-        uint256 endAmount;           // Auction end amount: sellOrder.takerAssetAmount
-        uint256 currentAmount;       // Calculated amount given block.timestamp
-        uint256 currentTimeSeconds;  // block.timestamp
-    }
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-    }
-
-    /// @dev Matches the buy and sell orders at an amount given the following: the current block time, the auction
-    ///      start time and the auction begin amount. The sell order is a an order at the lowest amount
-    ///      at the end of the auction. Excess from the match is transferred to the seller.
-    ///      Over time the price moves from beginAmount to endAmount given the current block.timestamp.
-    ///      sellOrder.expiryTimeSeconds is the end time of the auction.
-    ///      sellOrder.takerAssetAmount is the end amount of the auction (lowest possible amount).
-    ///      sellOrder.makerAssetData is the ABI encoded Asset Proxy data with the following data appended
-    ///      buyOrder.makerAssetData is the buyers bid on the auction, must meet the amount for the current block timestamp
-    ///      (uint256 beginTimeSeconds, uint256 beginAmount).
-    ///      This function reverts in the following scenarios:
-    ///         * Auction has not started (auctionDetails.currentTimeSeconds < auctionDetails.beginTimeSeconds)
-    ///         * Auction has expired (auctionDetails.endTimeSeconds < auctionDetails.currentTimeSeconds)
-    ///         * Amount is invalid: Buy order amount is too low (buyOrder.makerAssetAmount < auctionDetails.currentAmount)
-    ///         * Amount is invalid: Invalid begin amount (auctionDetails.beginAmount > auctionDetails.endAmount)
-    ///         * Any failure in the 0x Match Orders
-    /// @param buyOrder The Buyer's order. This order is for the current expected price of the auction.
-    /// @param sellOrder The Seller's order. This order is for the lowest amount (at the end of the auction).
-    /// @param buySignature Proof that order was created by the buyer.
-    /// @param sellSignature Proof that order was created by the seller.
-    /// @return matchedFillResults amounts filled and fees paid by maker and taker of matched orders.
-    function matchOrders(
-        LibOrder.Order memory buyOrder,
-        LibOrder.Order memory sellOrder,
-        bytes memory buySignature,
-        bytes memory sellSignature
-    )
-        public
-        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
-    {
-        AuctionDetails memory auctionDetails = getAuctionDetails(sellOrder);
-        // Ensure the auction has not yet started
-        require(
-            auctionDetails.currentTimeSeconds >= auctionDetails.beginTimeSeconds,
-            "AUCTION_NOT_STARTED"
-        );
-        // Ensure the auction has not expired. This will fail later in 0x but we can save gas by failing early
-        require(
-            sellOrder.expirationTimeSeconds > auctionDetails.currentTimeSeconds,
-            "AUCTION_EXPIRED"
-        );
-        // Validate the buyer amount is greater than the current auction amount
-        require(
-            buyOrder.makerAssetAmount >= auctionDetails.currentAmount,
-            "INVALID_AMOUNT"
-        );
-        // Match orders, maximally filling `buyOrder`
-        matchedFillResults = EXCHANGE.matchOrders(
-            buyOrder,
-            sellOrder,
-            buySignature,
-            sellSignature
-        );
-        // The difference in sellOrder.takerAssetAmount and current amount is given as spread to the matcher
-        // This may include additional spread from the buyOrder.makerAssetAmount and the currentAmount.
-        // e.g currentAmount is 30, sellOrder.takerAssetAmount is 10 and buyOrder.makerAssetamount is 40.
-        // 10 (40-30) is returned to the buyer, 20 (30-10) sent to the seller and 10 has previously
-        // been transferred to the seller during matchOrders
-        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
-        if (leftMakerAssetSpreadAmount > 0) {
-            // ERC20 Asset data itself is encoded as follows:
-            //
-            // | Area     | Offset | Length  | Contents                            |
-            // |----------|--------|---------|-------------------------------------|
-            // | Header   | 0      | 4       | function selector                   |
-            // | Params   |        | 1 * 32  | function parameters:                |
-            // |          | 4      | 12      |   1. token address padding          |
-            // |          | 16     | 20      |   2. token address                  |
-            bytes memory assetData = sellOrder.takerAssetData;
-            address token = assetData.readAddress(16);
-            // Calculate the excess from the buy order. This can occur if the buyer sends in a higher
-            // amount than the calculated current amount
-            uint256 buyerExcessAmount = safeSub(buyOrder.makerAssetAmount, auctionDetails.currentAmount);
-            uint256 sellerExcessAmount = safeSub(leftMakerAssetSpreadAmount, buyerExcessAmount);
-            // Return the difference between auctionDetails.currentAmount and sellOrder.takerAssetAmount
-            // to the seller
-            if (sellerExcessAmount > 0) {
-                IERC20Token(token).transfer(sellOrder.makerAddress, sellerExcessAmount);
-            }
-            // Return the difference between buyOrder.makerAssetAmount and auctionDetails.currentAmount
-            // to the buyer
-            if (buyerExcessAmount > 0) {
-                IERC20Token(token).transfer(buyOrder.makerAddress, buyerExcessAmount);
-            }
-        }
-        return matchedFillResults;
-    }
-
-    /// @dev Calculates the Auction Details for the given order
-    /// @param order The sell order
-    /// @return AuctionDetails
-    function getAuctionDetails(
-        LibOrder.Order memory order
-    )
-        public
-        returns (AuctionDetails memory auctionDetails)
-    {
-        uint256 makerAssetDataLength = order.makerAssetData.length;
-        // It is unknown the encoded data of makerAssetData, we assume the last 64 bytes
-        // are the Auction Details encoding.
-        // Auction Details is encoded as follows:
-        //
-        // | Area     | Offset | Length  | Contents                            |
-        // |----------|--------|---------|-------------------------------------|
-        // | Params   |        | 2 * 32  | parameters:                         |
-        // |          | -64    | 32      |   1. auction begin unix timestamp   |
-        // |          | -32    | 32      |   2. auction begin begin amount     |
-        // ERC20 asset data length is 4+32, 64 for auction details results in min length 100
-        require(
-            makerAssetDataLength >= 100,
-            "INVALID_ASSET_DATA"
-        );
-        uint256 auctionBeginTimeSeconds = order.makerAssetData.readUint256(makerAssetDataLength - 64);
-        uint256 auctionBeginAmount = order.makerAssetData.readUint256(makerAssetDataLength - 32);
-        // Ensure the auction has a valid begin time
-        require(
-            order.expirationTimeSeconds > auctionBeginTimeSeconds,
-            "INVALID_BEGIN_TIME"
-        );
-        uint256 auctionDurationSeconds = order.expirationTimeSeconds-auctionBeginTimeSeconds;
-        // Ensure the auction goes from high to low
-        uint256 minAmount = order.takerAssetAmount;
-        require(
-            auctionBeginAmount > minAmount,
-            "INVALID_AMOUNT"
-        );
-        uint256 amountDelta = auctionBeginAmount-minAmount;
-        // solhint-disable-next-line not-rely-on-time
-        uint256 timestamp = block.timestamp;
-        auctionDetails.beginTimeSeconds = auctionBeginTimeSeconds;
-        auctionDetails.endTimeSeconds = order.expirationTimeSeconds;
-        auctionDetails.beginAmount = auctionBeginAmount;
-        auctionDetails.endAmount = minAmount;
-        auctionDetails.currentTimeSeconds = timestamp;
-
-        uint256 remainingDurationSeconds = order.expirationTimeSeconds-timestamp;
-        if (timestamp < auctionBeginTimeSeconds) {
-            // If the auction has not yet begun the current amount is the auctionBeginAmount
-            auctionDetails.currentAmount = auctionBeginAmount;
-        } else if (timestamp >= order.expirationTimeSeconds) {
-            // If the auction has ended the current amount is the minAmount.
-            // Auction end time is guaranteed by 0x Exchange due to the order expiration
-            auctionDetails.currentAmount = minAmount;
-        } else {
-            auctionDetails.currentAmount = safeAdd(
-                minAmount,
-                safeDiv(
-                    safeMul(remainingDurationSeconds, amountDelta),
-                    auctionDurationSeconds
-                )
-            );
-        }
-        return auctionDetails;
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/Forwarder.sol
+++ b/contracts/extensions/contracts/Forwarder/Forwarder.sol
@@ -1,50 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./MixinWeth.sol";
-import "./MixinForwarderCore.sol";
-import "./libs/LibConstants.sol";
-import "./MixinAssets.sol";
-import "./MixinExchangeWrapper.sol";
-
-
-// solhint-disable no-empty-blocks
-contract Forwarder is
-    LibConstants,
-    MixinWeth,
-    MixinAssets,
-    MixinExchangeWrapper,
-    MixinForwarderCore
-{
-    constructor (
-        address _exchange,
-        bytes memory _zrxAssetData,
-        bytes memory _wethAssetData
-    )
-        public
-        LibConstants(
-            _exchange,
-            _zrxAssetData,
-            _wethAssetData
-        )
-        MixinForwarderCore()
-    {}
-}
--- a/contracts/extensions/contracts/Forwarder/MixinAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
@@ -1,143 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
-import "./libs/LibConstants.sol";
-import "./mixins/MAssets.sol";
-
-
-contract MixinAssets is
-    Ownable,
-    LibConstants,
-    MAssets
-{
-    using LibBytes for bytes;
-
-    bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)"));
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of ERC20 token to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        transferAssetToSender(assetData, amount);
-    }
-
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            transferERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            transferERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        bool success = token.call(abi.encodeWithSelector(
-            ERC20_TRANSFER_SELECTOR,
-            msg.sender,
-            amount
-        ));
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-        
-        // Check return data.
-        // If there is no return data, we assume the token incorrectly
-        // does not return a bool. In this case we expect it to revert
-        // on failure, which was handled above.
-        // If the token does return data, we require that it is a single
-        // value that evaluates to true.
-        assembly {
-            if returndatasize {
-                success := 0
-                if eq(returndatasize, 32) {
-                    // First 64 bytes of memory are reserved scratch space
-                    returndatacopy(0, 0, 32)
-                    success := mload(0)
-                }
-            }
-        }
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-    }
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        require(
-            amount == 1,
-            "INVALID_AMOUNT"
-        );
-        // Decode asset data.
-        address token = assetData.readAddress(16);
-        uint256 tokenId = assetData.readUint256(36);
-
-        // Perform transfer.
-        IERC721Token(token).transferFrom(
-            address(this),
-            msg.sender,
-            tokenId
-        );
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
@@ -1,260 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "./mixins/MExchangeWrapper.sol";
-import "@0x/contracts-libs/contracts/libs/LibAbiEncoder.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-
-
-contract MixinExchangeWrapper is
-    LibAbiEncoder,
-    LibFillResults,
-    LibMath,
-    LibConstants,
-    MExchangeWrapper
-{
-    /// @dev Fills the input order.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param signature Proof that order has been created by maker.
-    /// @return Amounts filled and fees paid by maker and taker.
-    function fillOrderNoThrow(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        bytes memory signature
-    )
-        internal
-        returns (FillResults memory fillResults)
-    {
-        // ABI encode calldata for `fillOrder`
-        bytes memory fillOrderCalldata = abiEncodeFillOrder(
-            order,
-            takerAssetFillAmount,
-            signature
-        );
-
-        address exchange = address(EXCHANGE);
-
-        // Call `fillOrder` and handle any exceptions gracefully
-        assembly {
-            let success := call(
-                gas,                                // forward all gas
-                exchange,                           // call address of Exchange contract
-                0,                                  // transfer 0 wei
-                add(fillOrderCalldata, 32),         // pointer to start of input (skip array length in first 32 bytes)
-                mload(fillOrderCalldata),           // length of input
-                fillOrderCalldata,                  // write output over input
-                128                                 // output size is 128 bytes
-            )
-            if success {
-                mstore(fillResults, mload(fillOrderCalldata))
-                mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
-                mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
-                mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
-            }
-        }
-        // fillResults values will be 0 by default if call was unsuccessful
-        return fillResults;
-    }
-
-    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param orders Array of order specifications.
-    /// @param wethSellAmount Desired amount of WETH to sell.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketSellWeth(
-        LibOrder.Order[] memory orders,
-        uint256 wethSellAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        bytes memory makerAssetData = orders[0].makerAssetData;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // We assume that asset being bought by taker is the same for each order.
-            // We assume that asset being sold by taker is WETH for each order.
-            orders[i].makerAssetData = makerAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of WETH to sell
-            uint256 remainingTakerAssetFillAmount = safeSub(wethSellAmount, totalFillResults.takerAssetFilledAmount);
-
-            // Attempt to sell the remaining amount of WETH
-            FillResults memory singleFillResults = fillOrderNoThrow(
-                orders[i],
-                remainingTakerAssetFillAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker
-            addFillResults(totalFillResults, singleFillResults);
-
-            // Stop execution if the entire amount of takerAsset has been sold
-            if (totalFillResults.takerAssetFilledAmount >= wethSellAmount) {
-                break;
-            }
-        }
-        return totalFillResults;
-    }
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    ///      The asset being sold by taker must always be WETH.
-    /// @param orders Array of order specifications.
-    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketBuyExactAmountWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        bytes memory makerAssetData = orders[0].makerAssetData;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // We assume that asset being bought by taker is the same for each order.
-            // We assume that asset being sold by taker is WETH for each order.
-            orders[i].makerAssetData = makerAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of makerAsset to buy
-            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
-
-            // Convert the remaining amount of makerAsset to buy into remaining amount
-            // of takerAsset to sell, assuming entire amount can be sold in the current order.
-            // We round up because the exchange rate computed by fillOrder rounds in favor
-            // of the Maker. In this case we want to overestimate the amount of takerAsset.
-            uint256 remainingTakerAssetFillAmount = getPartialAmountCeil(
-                orders[i].takerAssetAmount,
-                orders[i].makerAssetAmount,
-                remainingMakerAssetFillAmount
-            );
-
-            // Attempt to sell the remaining amount of takerAsset
-            FillResults memory singleFillResults = fillOrderNoThrow(
-                orders[i],
-                remainingTakerAssetFillAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker
-            addFillResults(totalFillResults, singleFillResults);
-
-            // Stop execution if the entire amount of makerAsset has been bought
-            uint256 makerAssetFilledAmount = totalFillResults.makerAssetFilledAmount;
-            if (makerAssetFilledAmount >= makerAssetFillAmount) {
-                break;
-            }
-        }
-
-        require(
-            makerAssetFilledAmount >= makerAssetFillAmount,
-            "COMPLETE_FILL_FAILED"
-        );
-        return totalFillResults;
-    }
-
-    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
-    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
-    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
-    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
-    ///      The asset being sold by taker must always be WETH. 
-    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
-    /// @param zrxBuyAmount Desired amount of ZRX to buy.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function marketBuyExactZrxWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 zrxBuyAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        // Do nothing if zrxBuyAmount == 0
-        if (zrxBuyAmount == 0) {
-            return totalFillResults;
-        }
-
-        bytes memory zrxAssetData = ZRX_ASSET_DATA;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-        uint256 zrxPurchased = 0;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // All of these are ZRX/WETH, so we can drop the respective assetData from calldata.
-            orders[i].makerAssetData = zrxAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of ZRX to buy.
-            uint256 remainingZrxBuyAmount = safeSub(zrxBuyAmount, zrxPurchased);
-
-            // Convert the remaining amount of ZRX to buy into remaining amount
-            // of WETH to sell, assuming entire amount can be sold in the current order.
-            // We round up because the exchange rate computed by fillOrder rounds in favor
-            // of the Maker. In this case we want to overestimate the amount of takerAsset.
-            uint256 remainingWethSellAmount = getPartialAmountCeil(
-                orders[i].takerAssetAmount,
-                safeSub(orders[i].makerAssetAmount, orders[i].takerFee),  // our exchange rate after fees 
-                remainingZrxBuyAmount
-            );
-
-            // Attempt to sell the remaining amount of WETH.
-            FillResults memory singleFillResult = fillOrderNoThrow(
-                orders[i],
-                remainingWethSellAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker.
-            addFillResults(totalFillResults, singleFillResult);
-            zrxPurchased = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid);
-
-            // Stop execution if the entire amount of ZRX has been bought.
-            if (zrxPurchased >= zrxBuyAmount) {
-                break;
-            }
-        }
-
-        require(
-            zrxPurchased >= zrxBuyAmount,
-            "COMPLETE_FILL_FAILED"
-        );
-        return totalFillResults;
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
@@ -1,214 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "./mixins/MWeth.sol";
-import "./mixins/MAssets.sol";
-import "./mixins/MExchangeWrapper.sol";
-import "./interfaces/IForwarderCore.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-
-
-contract MixinForwarderCore is
-    LibFillResults,
-    LibMath,
-    LibConstants,
-    MWeth,
-    MAssets,
-    MExchangeWrapper,
-    IForwarderCore
-{
-    using LibBytes for bytes;
-
-    /// @dev Constructor approves ERC20 proxy to transfer ZRX and WETH on this contract's behalf.
-    constructor ()
-        public
-    {
-        address proxyAddress = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
-        require(
-            proxyAddress != address(0),
-            "UNREGISTERED_ASSET_PROXY"
-        );
-        ETHER_TOKEN.approve(proxyAddress, MAX_UINT);
-        ZRX_TOKEN.approve(proxyAddress, MAX_UINT);
-    }
-
-    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketSellOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            FillResults memory orderFillResults,
-            FillResults memory feeOrderFillResults
-        )
-    {
-        // Convert ETH to WETH.
-        convertEthToWeth();
-
-        uint256 wethSellAmount;
-        uint256 zrxBuyAmount;
-        uint256 makerAssetAmountPurchased;
-        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
-            // Calculate amount of WETH that won't be spent on ETH fees.
-            wethSellAmount = getPartialAmountFloor(
-                PERCENTAGE_DENOMINATOR,
-                safeAdd(PERCENTAGE_DENOMINATOR, feePercentage),
-                msg.value
-            );
-            // Market sell available WETH.
-            // ZRX fees are paid with this contract's balance.
-            orderFillResults = marketSellWeth(
-                orders,
-                wethSellAmount,
-                signatures
-            );
-            // The fee amount must be deducted from the amount transfered back to sender.
-            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
-        } else {
-            // 5% of WETH is reserved for filling feeOrders and paying feeRecipient.
-            wethSellAmount = getPartialAmountFloor(
-                MAX_WETH_FILL_PERCENTAGE,
-                PERCENTAGE_DENOMINATOR,
-                msg.value
-            );
-            // Market sell 95% of WETH.
-            // ZRX fees are payed with this contract's balance.
-            orderFillResults = marketSellWeth(
-                orders,
-                wethSellAmount,
-                signatures
-            );
-            // Buy back all ZRX spent on fees.
-            zrxBuyAmount = orderFillResults.takerFeePaid;
-            feeOrderFillResults = marketBuyExactZrxWithWeth(
-                feeOrders,
-                zrxBuyAmount,
-                feeSignatures
-            );
-            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
-        }
-
-        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
-        // Refund remaining ETH to msg.sender.
-        transferEthFeeAndRefund(
-            orderFillResults.takerAssetFilledAmount,
-            feeOrderFillResults.takerAssetFilledAmount,
-            feePercentage,
-            feeRecipient
-        );
-
-        // Transfer purchased assets to msg.sender.
-        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
-    }
-
-    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketBuyOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            FillResults memory orderFillResults,
-            FillResults memory feeOrderFillResults
-        )
-    {
-        // Convert ETH to WETH.
-        convertEthToWeth();
-
-        uint256 zrxBuyAmount;
-        uint256 makerAssetAmountPurchased;
-        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
-            // If the makerAsset is ZRX, it is not necessary to pay fees out of this
-            // contracts's ZRX balance because fees are factored into the price of the order.
-            orderFillResults = marketBuyExactZrxWithWeth(
-                orders,
-                makerAssetFillAmount,
-                signatures
-            );
-            // The fee amount must be deducted from the amount transfered back to sender.
-            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
-        } else {
-            // Attemp to purchase desired amount of makerAsset.
-            // ZRX fees are payed with this contract's balance.
-            orderFillResults = marketBuyExactAmountWithWeth(
-                orders,
-                makerAssetFillAmount,
-                signatures
-            );
-            // Buy back all ZRX spent on fees.
-            zrxBuyAmount = orderFillResults.takerFeePaid;
-            feeOrderFillResults = marketBuyExactZrxWithWeth(
-                feeOrders,
-                zrxBuyAmount,
-                feeSignatures
-            );
-            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
-        }
-
-        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
-        // Refund remaining ETH to msg.sender.
-        transferEthFeeAndRefund(
-            orderFillResults.takerAssetFilledAmount,
-            feeOrderFillResults.takerAssetFilledAmount,
-            feePercentage,
-            feeRecipient
-        );
-
-        // Transfer purchased assets to msg.sender.
-        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
@@ -1,113 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-import "./libs/LibConstants.sol";
-import "./mixins/MWeth.sol";
-
-
-contract MixinWeth is
-    LibMath,
-    LibConstants,
-    MWeth
-{
-    /// @dev Default payabale function, this allows us to withdraw WETH
-    function ()
-        public
-        payable
-    {
-        require(
-            msg.sender == address(ETHER_TOKEN),
-            "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY"
-        );
-    }
-
-    /// @dev Converts message call's ETH value into WETH.
-    function convertEthToWeth()
-        internal
-    {
-        require(
-            msg.value > 0,
-            "INVALID_MSG_VALUE"
-        );
-        ETHER_TOKEN.deposit.value(msg.value)();
-    }
-
-    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
-    ///      Refunds any excess ETH to msg.sender.
-    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
-    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    function transferEthFeeAndRefund(
-        uint256 wethSoldExcludingFeeOrders,
-        uint256 wethSoldForZrx,
-        uint256 feePercentage,
-        address feeRecipient
-    )
-        internal
-    {
-        // Ensure feePercentage is less than 5%.
-        require(
-            feePercentage <= MAX_FEE_PERCENTAGE,
-            "FEE_PERCENTAGE_TOO_LARGE"
-        );
-
-        // Ensure that no extra WETH owned by this contract has been sold.
-        uint256 wethSold = safeAdd(wethSoldExcludingFeeOrders, wethSoldForZrx);
-        require(
-            wethSold <= msg.value,
-            "OVERSOLD_WETH"
-        );
-
-        // Calculate amount of WETH that hasn't been sold.
-        uint256 wethRemaining = safeSub(msg.value, wethSold);
-
-        // Calculate ETH fee to pay to feeRecipient.
-        uint256 ethFee = getPartialAmountFloor(
-            feePercentage,
-            PERCENTAGE_DENOMINATOR,
-            wethSoldExcludingFeeOrders
-        );
-
-        // Ensure fee is less than amount of WETH remaining.
-        require(
-            ethFee <= wethRemaining,
-            "INSUFFICIENT_ETH_REMAINING"
-        );
-    
-        // Do nothing if no WETH remaining
-        if (wethRemaining > 0) {
-            // Convert remaining WETH to ETH
-            ETHER_TOKEN.withdraw(wethRemaining);
-
-            // Pay ETH to feeRecipient
-            if (ethFee > 0) {
-                feeRecipient.transfer(ethFee);
-            }
-
-            // Refund remaining ETH to msg.sender.
-            uint256 ethRefund = safeSub(wethRemaining, ethFee);
-            if (ethRefund > 0) {
-                msg.sender.transfer(ethRefund);
-            }
-        }
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
@@ -1,34 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IAssets {
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of ERC20 token to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
@@ -1,30 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./IForwarderCore.sol";
-import "./IAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract IForwarder is
-    IForwarderCore,
-    IAssets
-{}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
@@ -1,80 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-
-
-contract IForwarderCore {
-
-    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketSellOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
-
-    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketBuyOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
-}
--- a/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
@@ -1,62 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-tokens/contracts/tokens/EtherToken/IEtherToken.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-
-
-contract LibConstants {
-
-    using LibBytes for bytes;
-
-    bytes4 constant internal ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
-    bytes4 constant internal ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
-    uint256 constant internal MAX_UINT = 2**256 - 1;
-    uint256 constant internal PERCENTAGE_DENOMINATOR = 10**18; 
-    uint256 constant internal MAX_FEE_PERCENTAGE = 5 * PERCENTAGE_DENOMINATOR / 100;         // 5%
-    uint256 constant internal MAX_WETH_FILL_PERCENTAGE = 95 * PERCENTAGE_DENOMINATOR / 100;  // 95%
- 
-     // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    IEtherToken internal ETHER_TOKEN;
-    IERC20Token internal ZRX_TOKEN;
-    bytes internal ZRX_ASSET_DATA;
-    bytes internal WETH_ASSET_DATA;
-    // solhint-enable var-name-mixedcase
-
-    constructor (
-        address _exchange,
-        bytes memory _zrxAssetData,
-        bytes memory _wethAssetData
-    )
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-        ZRX_ASSET_DATA = _zrxAssetData;
-        WETH_ASSET_DATA = _wethAssetData;
-
-        address etherToken = _wethAssetData.readAddress(16);
-        address zrxToken = _zrxAssetData.readAddress(16);
-        ETHER_TOKEN = IEtherToken(etherToken);
-        ZRX_TOKEN = IERC20Token(zrxToken);
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
@@ -1,34 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-// solhint-disable
-pragma solidity ^0.4.24;
-
-
-/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
-contract LibForwarderErrors {
-    string constant FEE_PERCENTAGE_TOO_LARGE = "FEE_PROPORTION_TOO_LARGE";                        // Provided fee percentage greater than 5%.
-    string constant INSUFFICIENT_ETH_REMAINING = "INSUFFICIENT_ETH_REMAINING";                    // Not enough ETH remaining to pay feeRecipient.
-    string constant OVERSOLD_WETH = "OVERSOLD_WETH";                                              // More WETH sold than provided with current message call.
-    string constant COMPLETE_FILL_FAILED = "COMPLETE_FILL_FAILED";                                // Desired purchase amount not completely filled (required for ZRX fees only).
-    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                          // Asset transfer failed.
-    string constant UNSUPPORTED_ASSET_PROXY = "UNSUPPORTED_ASSET_PROXY";                          // Proxy in assetData not supported.
-    string constant DEFAULT_FUNCTION_WETH_CONTRACT_ONLY = "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY";  // Fallback function may only be used for WETH withdrawals.
-    string constant INVALID_MSG_VALUE = "INVALID_MSG_VALUE";                                      // msg.value must be greater than 0.
-    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                                            // Amount must equal 1.
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
@@ -1,53 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "../interfaces/IAssets.sol";
-
-
-contract MAssets is
-    IAssets
-{
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
@@ -1,87 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-
-
-contract MExchangeWrapper {
-
-    /// @dev Fills the input order.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param signature Proof that order has been created by maker.
-    /// @return Amounts filled and fees paid by maker and taker.
-    function fillOrderNoThrow(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        bytes memory signature
-    )
-        internal
-        returns (LibFillResults.FillResults memory fillResults);
-
-    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param orders Array of order specifications.
-    /// @param wethSellAmount Desired amount of WETH to sell.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketSellWeth(
-        LibOrder.Order[] memory orders,
-        uint256 wethSellAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    ///      The asset being sold by taker must always be WETH.
-    /// @param orders Array of order specifications.
-    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketBuyExactAmountWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-
-    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
-    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
-    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
-    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
-    ///      The asset being sold by taker must always be WETH. 
-    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
-    /// @param zrxBuyAmount Desired amount of ZRX to buy.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function marketBuyExactZrxWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 zrxBuyAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
@@ -1,41 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract MWeth {
-
-    /// @dev Converts message call's ETH value into WETH.
-    function convertEthToWeth()
-        internal;
-
-    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
-    ///      Refunds any excess ETH to msg.sender.
-    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
-    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    function transferEthFeeAndRefund(
-        uint256 wethSoldExcludingFeeOrders,
-        uint256 wethSoldForZrx,
-        uint256 feePercentage,
-        address feeRecipient
-    )
-        internal;
-}
--- a/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
+++ b/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
@@ -1,195 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
-import "./mixins/MAssets.sol";
-import "./libs/LibConstants.sol";
-
-
-contract MixinAssets is
-    MAssets,
-    Ownable,
-    LibConstants
-{
-    using LibBytes for bytes;
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        transferAssetToSender(assetData, amount);
-    }
-
-    /// @dev Approves or disapproves an AssetProxy to spend asset.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveAssetProxy(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            approveERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            approveERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            transferERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            transferERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        // 4 byte id + 12 0 bytes before ABI encoded token address.
-        address token = assetData.readAddress(16);
-
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        bool success = token.call(abi.encodeWithSelector(
-            ERC20_TRANSFER_SELECTOR,
-            msg.sender,
-            amount
-        ));
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-        
-        // Check return data.
-        // If there is no return data, we assume the token incorrectly
-        // does not return a bool. In this case we expect it to revert
-        // on failure, which was handled above.
-        // If the token does return data, we require that it is a single
-        // value that evaluates to true.
-        assembly {
-            if returndatasize {
-                success := 0
-                if eq(returndatasize, 32) {
-                    // First 64 bytes of memory are reserved scratch space
-                    returndatacopy(0, 0, 32)
-                    success := mload(0)
-                }
-            }
-        }
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-    }
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        require(
-            amount == 1,
-            "INVALID_AMOUNT"
-        );
-        // Decode asset data.
-        // 4 byte id + 12 0 bytes before ABI encoded token address.
-        address token = assetData.readAddress(16);
-        // 4 byte id + 32 byte ABI encoded token address before token id.
-        uint256 tokenId = assetData.readUint256(36);
-
-        // Perform transfer.
-        IERC721Token(token).transferFrom(
-            address(this),
-            msg.sender,
-            tokenId
-        );
-    }
-
-    /// @dev Sets approval for ERC20 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-        require(
-            IERC20Token(token).approve(ERC20_PROXY_ADDRESS, amount),
-            "APPROVAL_FAILED"
-        );
-    }
-
-    /// @dev Sets approval for ERC721 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-        bool approval = amount >= 1;
-        IERC721Token(token).setApprovalForAll(ERC721_PROXY_ADDRESS, approval);
-    }
-}
--- a/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
+++ b/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
@@ -1,86 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-
-
-contract MixinMatchOrders is
-    Ownable,
-    LibConstants
-{
-    /// @dev Match two complementary orders that have a profitable spread.
-    ///      Each order is filled at their respective price point. However, the calculations are
-    ///      carried out as though the orders are both being filled at the right order's price point.
-    ///      The profit made by the left order is then used to fill the right order as much as possible.
-    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
-    /// @param leftOrder First order to match.
-    /// @param rightOrder Second order to match.
-    /// @param leftSignature Proof that order was created by the left maker.
-    /// @param rightSignature Proof that order was created by the right maker.
-    function matchOrders(
-        LibOrder.Order memory leftOrder,
-        LibOrder.Order memory rightOrder,
-        bytes memory leftSignature,
-        bytes memory rightSignature
-    )
-        public
-        onlyOwner
-    {
-        // Match orders, maximally filling `leftOrder`
-        LibFillResults.MatchedFillResults memory matchedFillResults = EXCHANGE.matchOrders(
-            leftOrder,
-            rightOrder,
-            leftSignature,
-            rightSignature
-        );
-
-        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
-        uint256 rightOrderTakerAssetAmount = rightOrder.takerAssetAmount;
-
-        // Do not attempt to call `fillOrder` if no spread was taken or `rightOrder` has been completely filled
-        if (leftMakerAssetSpreadAmount == 0 || matchedFillResults.right.takerAssetFilledAmount == rightOrderTakerAssetAmount) {
-            return;
-        }
-
-        // The `assetData` fields of the `rightOrder` could have been null for the `matchOrders` call. We reassign them before calling `fillOrder`.
-        rightOrder.makerAssetData = leftOrder.takerAssetData;
-        rightOrder.takerAssetData = leftOrder.makerAssetData;
-
-        // Query `rightOrder` info to check if it has been completely filled
-        // We need to make this check in case the `rightOrder` was partially filled before the `matchOrders` call
-        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(rightOrder);
-
-        // Do not attempt to call `fillOrder` if order has been completely filled
-        if (orderInfo.orderTakerAssetFilledAmount == rightOrderTakerAssetAmount) {
-            return;
-        }
-
-        // We do not need to pass in a signature since it was already validated in the `matchOrders` call
-        EXCHANGE.fillOrder(
-            rightOrder,
-            leftMakerAssetSpreadAmount,
-            ""
-        );
-    }
-}
--- a/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
+++ b/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
@@ -1,38 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "./libs/LibConstants.sol";
-import "./MixinMatchOrders.sol";
-import "./MixinAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract OrderMatcher is
-    MixinMatchOrders,
-    MixinAssets
-{
-    constructor (address _exchange)
-        public
-        LibConstants(_exchange)
-        Ownable()
-    {}
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
@@ -1,43 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IAssets {
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-
-    /// @dev Approves or disapproves an AssetProxy to spend asset.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveAssetProxy(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
@@ -1,43 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-
-
-contract IMatchOrders {
-
-    /// @dev Match two complementary orders that have a profitable spread.
-    ///      Each order is filled at their respective price point. However, the calculations are
-    ///      carried out as though the orders are both being filled at the right order's price point.
-    ///      The profit made by the left order is then used to fill the right order as much as possible.
-    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
-    /// @param leftOrder First order to match.
-    /// @param rightOrder Second order to match.
-    /// @param leftSignature Proof that order was created by the left maker.
-    /// @param rightSignature Proof that order was created by the right maker.
-    function matchOrders(
-        LibOrder.Order memory leftOrder,
-        LibOrder.Order memory rightOrder,
-        bytes memory leftSignature,
-        bytes memory rightSignature
-    )
-        public;
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
@@ -1,31 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contract-utils/contracts/utils/Ownable/IOwnable.sol";
-import "./IMatchOrders.sol";
-import "./IAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract IOrderMatcher is
-    IOwnable,
-    IMatchOrders,
-    IAssets
-{}
--- a/contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol
+++ b/contracts/extensions/contracts/OrderMatcher/libs/LibConstants.sol
@@ -1,56 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-
-
-contract LibConstants {
-
-    // bytes4(keccak256("transfer(address,uint256)"))
-    bytes4 constant internal ERC20_TRANSFER_SELECTOR = 0xa9059cbb;
-    // bytes4(keccak256("ERC20Token(address)"))
-    bytes4 constant internal ERC20_DATA_ID = 0xf47261b0;
-    // bytes4(keccak256("ERC721Token(address,uint256)"))
-    bytes4 constant internal ERC721_DATA_ID = 0x02571792;
- 
-     // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    address internal ERC20_PROXY_ADDRESS;
-    address internal ERC721_PROXY_ADDRESS;
-    // solhint-enable var-name-mixedcase
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-
-        ERC20_PROXY_ADDRESS = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
-        require(
-            ERC20_PROXY_ADDRESS != address(0),
-            "UNREGISTERED_ASSET_PROXY"
-        );
-
-        ERC721_PROXY_ADDRESS = EXCHANGE.getAssetProxy(ERC721_DATA_ID);
-        require(
-            ERC721_PROXY_ADDRESS != address(0),
-            "UNREGISTERED_ASSET_PROXY"
-        );
-    }
-}
--- a/contracts/extensions/contracts/OrderMatcher/mixins/MAssets.sol
+++ b/contracts/extensions/contracts/OrderMatcher/mixins/MAssets.sol
@@ -1,71 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "../interfaces/IAssets.sol";
-
-
-contract MAssets is
-    IAssets
-{
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Sets approval for ERC20 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Sets approval for ERC721 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-}
--- a/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
+++ b/contracts/extensions/contracts/OrderValidator/OrderValidator.sol
@@ -1,218 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-
-
-contract OrderValidator {
-
-    using LibBytes for bytes;
-
-    bytes4 constant internal ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
-    bytes4 constant internal ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
-
-    struct TraderInfo {
-        uint256 makerBalance;       // Maker's balance of makerAsset
-        uint256 makerAllowance;     // Maker's allowance to corresponding AssetProxy
-        uint256 takerBalance;       // Taker's balance of takerAsset
-        uint256 takerAllowance;     // Taker's allowance to corresponding AssetProxy
-        uint256 makerZrxBalance;    // Maker's balance of ZRX
-        uint256 makerZrxAllowance;  // Maker's allowance of ZRX to ERC20Proxy
-        uint256 takerZrxBalance;    // Taker's balance of ZRX
-        uint256 takerZrxAllowance;  // Taker's allowance of ZRX to ERC20Proxy
-    }
-
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    bytes internal ZRX_ASSET_DATA;
-    // solhint-enable var-name-mixedcase
-
-    constructor (address _exchange, bytes memory _zrxAssetData)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-        ZRX_ASSET_DATA = _zrxAssetData;
-    }
-
-    /// @dev Fetches information for order and maker/taker of order.
-    /// @param order The order structure.
-    /// @param takerAddress Address that will be filling the order.
-    /// @return OrderInfo and TraderInfo instances for given order.
-    function getOrderAndTraderInfo(LibOrder.Order memory order, address takerAddress)
-        public
-        view
-        returns (LibOrder.OrderInfo memory orderInfo, TraderInfo memory traderInfo)
-    {
-        orderInfo = EXCHANGE.getOrderInfo(order);
-        traderInfo = getTraderInfo(order, takerAddress);
-        return (orderInfo, traderInfo);
-    }
-
-    /// @dev Fetches information for all passed in orders and the makers/takers of each order.
-    /// @param orders Array of order specifications.
-    /// @param takerAddresses Array of taker addresses corresponding to each order.
-    /// @return Arrays of OrderInfo and TraderInfo instances that correspond to each order.
-    function getOrdersAndTradersInfo(LibOrder.Order[] memory orders, address[] memory takerAddresses)
-        public
-        view
-        returns (LibOrder.OrderInfo[] memory ordersInfo, TraderInfo[] memory tradersInfo)
-    {
-        ordersInfo = EXCHANGE.getOrdersInfo(orders);
-        tradersInfo = getTradersInfo(orders, takerAddresses);
-        return (ordersInfo, tradersInfo);
-    }
-
-    /// @dev Fetches balance and allowances for maker and taker of order.
-    /// @param order The order structure.
-    /// @param takerAddress Address that will be filling the order.
-    /// @return Balances and allowances of maker and taker of order.
-    function getTraderInfo(LibOrder.Order memory order, address takerAddress)
-        public
-        view
-        returns (TraderInfo memory traderInfo)
-    {
-        (traderInfo.makerBalance, traderInfo.makerAllowance) = getBalanceAndAllowance(order.makerAddress, order.makerAssetData);
-        (traderInfo.takerBalance, traderInfo.takerAllowance) = getBalanceAndAllowance(takerAddress, order.takerAssetData);
-        bytes memory zrxAssetData = ZRX_ASSET_DATA;
-        (traderInfo.makerZrxBalance, traderInfo.makerZrxAllowance) = getBalanceAndAllowance(order.makerAddress, zrxAssetData);
-        (traderInfo.takerZrxBalance, traderInfo.takerZrxAllowance) = getBalanceAndAllowance(takerAddress, zrxAssetData);
-        return traderInfo;
-    }
-
-    /// @dev Fetches balances and allowances of maker and taker for each provided order.
-    /// @param orders Array of order specifications.
-    /// @param takerAddresses Array of taker addresses corresponding to each order.
-    /// @return Array of balances and allowances for maker and taker of each order.
-    function getTradersInfo(LibOrder.Order[] memory orders, address[] memory takerAddresses)
-        public
-        view
-        returns (TraderInfo[] memory)
-    {
-        uint256 ordersLength = orders.length;
-        TraderInfo[] memory tradersInfo = new TraderInfo[](ordersLength);
-        for (uint256 i = 0; i != ordersLength; i++) {
-            tradersInfo[i] = getTraderInfo(orders[i], takerAddresses[i]);
-        }
-        return tradersInfo;
-    }
-
-    /// @dev Fetches token balances and allowances of an address to given assetProxy. Supports ERC20 and ERC721.
-    /// @param target Address to fetch balances and allowances of.
-    /// @param assetData Encoded data that can be decoded by a specified proxy contract when transferring asset.
-    /// @return Balance of asset and allowance set to given proxy of asset.
-    ///         For ERC721 tokens, these values will always be 1 or 0.
-    function getBalanceAndAllowance(address target, bytes memory assetData)
-        public
-        view
-        returns (uint256 balance, uint256 allowance)
-    {
-        bytes4 assetProxyId = assetData.readBytes4(0);
-        address token = assetData.readAddress(16);
-        address assetProxy = EXCHANGE.getAssetProxy(assetProxyId);
-
-        if (assetProxyId == ERC20_DATA_ID) {
-            // Query balance
-            balance = IERC20Token(token).balanceOf(target);
-
-            // Query allowance
-            allowance = IERC20Token(token).allowance(target, assetProxy);
-        } else if (assetProxyId == ERC721_DATA_ID) {
-            uint256 tokenId = assetData.readUint256(36);
-
-            // Query owner of tokenId
-            address owner = getERC721TokenOwner(token, tokenId);
-
-            // Set balance to 1 if tokenId is owned by target
-            balance = target == owner ? 1 : 0;
-
-            // Check if ERC721Proxy is approved to spend tokenId
-            bool isApproved = IERC721Token(token).isApprovedForAll(target, assetProxy);
-            
-            // Set alowance to 1 if ERC721Proxy is approved to spend tokenId
-            allowance = isApproved ? 1 : 0;
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-        return (balance, allowance);
-    }
-
-    /// @dev Fetches token balances and allowances of an address for each given assetProxy. Supports ERC20 and ERC721.
-    /// @param target Address to fetch balances and allowances of.
-    /// @param assetData Array of encoded byte arrays that can be decoded by a specified proxy contract when transferring asset.
-    /// @return Balances and allowances of assets.
-    ///         For ERC721 tokens, these values will always be 1 or 0.
-    function getBalancesAndAllowances(address target, bytes[] memory assetData)
-        public
-        view
-        returns (uint256[] memory, uint256[] memory)
-    {
-        uint256 length = assetData.length;
-        uint256[] memory balances = new uint256[](length);
-        uint256[] memory allowances = new uint256[](length);
-        for (uint256 i = 0; i != length; i++) {
-            (balances[i], allowances[i]) = getBalanceAndAllowance(target, assetData[i]);
-        }
-        return (balances, allowances);
-    }
-
-    /// @dev Calls `token.ownerOf(tokenId)`, but returns a null owner instead of reverting on an unowned token.
-    /// @param token Address of ERC721 token.
-    /// @param tokenId The identifier for the specific NFT.
-    /// @return Owner of tokenId or null address if unowned.
-    function getERC721TokenOwner(address token, uint256 tokenId)
-        public
-        view
-        returns (address owner)
-    {
-        assembly {
-            // load free memory pointer
-            let cdStart := mload(64)
-
-            // bytes4(keccak256(ownerOf(uint256))) = 0x6352211e
-            mstore(cdStart, 0x6352211e00000000000000000000000000000000000000000000000000000000)
-            mstore(add(cdStart, 4), tokenId)
-
-            // staticcall `ownerOf(tokenId)`
-            // `ownerOf` will revert if tokenId is not owned
-            let success := staticcall(
-                gas,      // forward all gas
-                token,    // call token contract
-                cdStart,  // start of calldata
-                36,       // length of input is 36 bytes
-                cdStart,  // write output over input
-                32        // size of output is 32 bytes
-            )
-
-            // Success implies that tokenId is owned
-            // Copy owner from return data if successful
-            if success {
-                owner := mload(cdStart)
-            }    
-        }
-
-        // Owner initialized to address(0), no need to modify if call is unsuccessful
-        return owner;
-    }
-}
--- a/contracts/extensions/package.json
+++ b/contracts/extensions/package.json
@@ -1,93 +0,0 @@
-{
-    "name": "@0x/contracts-extensions",
-    "version": "1.2.2",
-    "engines": {
-        "node": ">=6.12"
-    },
-    "description": "Smart contract extensions of 0x protocol",
-    "main": "lib/src/index.js",
-    "directories": {
-        "test": "test"
-    },
-    "scripts": {
-        "build": "yarn pre_build && tsc -b",
-        "build:ci": "yarn build",
-        "pre_build": "run-s compile generate_contract_wrappers",
-        "test": "yarn run_mocha",
-        "rebuild_and_test": "run-s build test",
-        "test:coverage": "SOLIDITY_COVERAGE=true run-s build run_mocha coverage:report:text coverage:report:lcov",
-        "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
-        "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
-        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler",
-        "watch": "sol-compiler -w",
-        "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
-        "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
-        "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
-        "coverage:report:text": "istanbul report text",
-        "coverage:report:html": "istanbul report html && open coverage/index.html",
-        "profiler:report:html": "istanbul report html && open coverage/index.html",
-        "coverage:report:lcov": "istanbul report lcov",
-        "test:circleci": "yarn test",
-        "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
-    },
-    "config": {
-        "abis": "generated-artifacts/@(BalanceThresholdFilter|DutchAuction|Forwarder|OrderMatcher|OrderValidator).json"
-    },
-    "repository": {
-        "type": "git",
-        "url": "https://github.com/0xProject/0x-monorepo.git"
-    },
-    "license": "Apache-2.0",
-    "bugs": {
-        "url": "https://github.com/0xProject/0x-monorepo/issues"
-    },
-    "homepage": "https://github.com/0xProject/0x-monorepo/contracts/extensions/README.md",
-    "devDependencies": {
-        "@0x/abi-gen": "^1.0.22",
-        "@0x/contract-wrappers": "^5.0.0",
-        "@0x/contracts-test-utils": "^2.0.0",
-        "@0x/dev-utils": "^1.0.24",
-        "@0x/sol-compiler": "^2.0.2",
-        "@0x/subproviders": "^2.1.11",
-        "@0x/tslint-config": "^2.0.2",
-        "@types/bn.js": "^4.11.0",
-        "@types/lodash": "4.14.104",
-        "@types/node": "*",
-        "@types/yargs": "^10.0.0",
-        "chai": "^4.0.1",
-        "chai-as-promised": "^7.1.0",
-        "chai-bignumber": "^2.0.1",
-        "dirty-chai": "^2.0.1",
-        "ethereumjs-abi": "0.6.5",
-        "make-promises-safe": "^1.1.0",
-        "mocha": "^4.1.0",
-        "npm-run-all": "^4.1.2",
-        "shx": "^0.2.2",
-        "solhint": "^1.4.1",
-        "tslint": "5.11.0",
-        "typescript": "3.0.1",
-        "yargs": "^10.0.3"
-    },
-    "dependencies": {
-        "@0x/base-contract": "^3.0.13",
-        "@0x/contracts-interfaces": "^1.0.5",
-        "@0x/contracts-libs": "^1.0.5",
-        "@0x/contracts-protocol": "^2.2.2",
-        "@0x/contracts-tokens": "^1.0.5",
-        "@0x/contracts-utils": "^1.0.5",
-        "@0x/order-utils": "^3.1.2",
-        "@0x/types": "^1.5.2",
-        "@0x/typescript-typings": "^3.0.8",
-        "@0x/utils": "^3.0.1",
-        "@0x/web3-wrapper": "^3.2.4",
-        "@types/js-combinatorics": "^0.5.29",
-        "bn.js": "^4.11.8",
-        "ethereum-types": "^1.1.6",
-        "ethereumjs-util": "^5.1.1",
-        "lodash": "^4.17.5"
-    },
-    "publishConfig": {
-        "access": "public"
-    }
-}
--- a/contracts/extensions/src/artifacts/index.ts
+++ b/contracts/extensions/src/artifacts/index.ts
@@ -1,15 +0,0 @@
-import { ContractArtifact } from 'ethereum-types';
-
-import * as BalanceThresholdFilter from '../../generated-artifacts/BalanceThresholdFilter.json';
-import * as DutchAuction from '../../generated-artifacts/DutchAuction.json';
-import * as Forwarder from '../../generated-artifacts/Forwarder.json';
-import * as OrderMatcher from '../../generated-artifacts/OrderMatcher.json';
-import * as OrderValidator from '../../generated-artifacts/OrderValidator.json';
-
-export const artifacts = {
-    BalanceThresholdFilter: BalanceThresholdFilter as ContractArtifact,
-    DutchAuction: DutchAuction as ContractArtifact,
-    Forwarder: Forwarder as ContractArtifact,
-    OrderMatcher: OrderMatcher as ContractArtifact,
-    OrderValidator: OrderValidator as ContractArtifact,
-};
--- a/contracts/extensions/src/index.ts
+++ b/contracts/extensions/src/index.ts
@@ -1,2 +0,0 @@
-export * from './artifacts';
-export * from './wrappers';
--- a/contracts/extensions/src/wrappers/index.ts
+++ b/contracts/extensions/src/wrappers/index.ts
@@ -1,5 +0,0 @@
-export * from '../../generated-wrappers/balance_threshold_filter';
-export * from '../../generated-wrappers/dutch_auction';
-export * from '../../generated-wrappers/forwarder';
-export * from '../../generated-wrappers/order_matcher';
-export * from '../../generated-wrappers/order_validator';
--- a/contracts/extensions/test/extensions/balance_threshold_filter.ts
+++ b/contracts/extensions/test/extensions/balance_threshold_filter.ts
--- a/contracts/extensions/test/extensions/dutch_auction.ts
+++ b/contracts/extensions/test/extensions/dutch_auction.ts
@@ -1,378 +0,0 @@
-import { DutchAuctionWrapper } from '@0x/contract-wrappers';
-import {
-    artifacts as protocolArtifacts,
-    ERC20Wrapper,
-    ERC721Wrapper,
-    ExchangeContract,
-    ExchangeWrapper,
-} from '@0x/contracts-protocol';
-import {
-    chaiSetup,
-    constants,
-    ContractName,
-    ERC20BalancesByOwner,
-    expectTransactionFailedAsync,
-    getLatestBlockTimestampAsync,
-    OrderFactory,
-    provider,
-    txDefaults,
-    web3Wrapper,
-} from '@0x/contracts-test-utils';
-import {
-    artifacts as tokensArtifacts,
-    DummyERC20TokenContract,
-    DummyERC721TokenContract,
-    WETH9Contract,
-} from '@0x/contracts-tokens';
-import { BlockchainLifecycle } from '@0x/dev-utils';
-import { assetDataUtils, generatePseudoRandomSalt } from '@0x/order-utils';
-import { RevertReason, SignedOrder } from '@0x/types';
-import { BigNumber } from '@0x/utils';
-import { Web3Wrapper } from '@0x/web3-wrapper';
-import * as chai from 'chai';
-import * as _ from 'lodash';
-
-import { DutchAuctionContract } from '../../generated-wrappers/dutch_auction';
-import { artifacts } from '../../src/artifacts';
-import { DutchAuctionTestWrapper } from '../utils/dutch_auction_test_wrapper';
-
-chaiSetup.configure();
-const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-const DECIMALS_DEFAULT = 18;
-
-describe(ContractName.DutchAuction, () => {
-    let makerAddress: string;
-    let owner: string;
-    let takerAddress: string;
-    let feeRecipientAddress: string;
-    let defaultMakerAssetAddress: string;
-
-    let zrxToken: DummyERC20TokenContract;
-    let erc20TokenA: DummyERC20TokenContract;
-    let erc721Token: DummyERC721TokenContract;
-    let dutchAuctionContract: DutchAuctionContract;
-    let wethContract: WETH9Contract;
-
-    let sellerOrderFactory: OrderFactory;
-    let buyerOrderFactory: OrderFactory;
-    let erc20Wrapper: ERC20Wrapper;
-    let erc20Balances: ERC20BalancesByOwner;
-    let currentBlockTimestamp: number;
-    let auctionBeginTimeSeconds: BigNumber;
-    let auctionEndTimeSeconds: BigNumber;
-    let auctionBeginAmount: BigNumber;
-    let auctionEndAmount: BigNumber;
-    let sellOrder: SignedOrder;
-    let buyOrder: SignedOrder;
-    let erc721MakerAssetIds: BigNumber[];
-    const tenMinutesInSeconds = 10 * 60;
-
-    let dutchAuctionTestWrapper: DutchAuctionTestWrapper;
-    let defaultERC20MakerAssetData: string;
-
-    before(async () => {
-        await blockchainLifecycle.startAsync();
-        const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
-
-        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
-
-        const numDummyErc20ToDeploy = 2;
-        [erc20TokenA, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
-            numDummyErc20ToDeploy,
-            constants.DUMMY_TOKEN_DECIMALS,
-        );
-        const erc20Proxy = await erc20Wrapper.deployProxyAsync();
-        await erc20Wrapper.setBalancesAndAllowancesAsync();
-
-        const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
-        [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
-        const erc721Proxy = await erc721Wrapper.deployProxyAsync();
-        await erc721Wrapper.setBalancesAndAllowancesAsync();
-        const erc721Balances = await erc721Wrapper.getBalancesAsync();
-        erc721MakerAssetIds = erc721Balances[makerAddress][erc721Token.address];
-
-        wethContract = await WETH9Contract.deployFrom0xArtifactAsync(tokensArtifacts.WETH9, provider, txDefaults);
-        erc20Wrapper.addDummyTokenContract(wethContract as any);
-
-        const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
-        const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
-            protocolArtifacts.Exchange,
-            provider,
-            txDefaults,
-            zrxAssetData,
-        );
-        const exchangeWrapper = new ExchangeWrapper(exchangeInstance, provider);
-        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
-        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
-
-        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
-            from: owner,
-        });
-        await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
-            from: owner,
-        });
-
-        const dutchAuctionInstance = await DutchAuctionContract.deployFrom0xArtifactAsync(
-            artifacts.DutchAuction,
-            provider,
-            txDefaults,
-            exchangeInstance.address,
-        );
-        dutchAuctionContract = new DutchAuctionContract(
-            dutchAuctionInstance.abi,
-            dutchAuctionInstance.address,
-            provider,
-        );
-        dutchAuctionTestWrapper = new DutchAuctionTestWrapper(dutchAuctionInstance, provider);
-
-        defaultMakerAssetAddress = erc20TokenA.address;
-        const defaultTakerAssetAddress = wethContract.address;
-
-        // Set up taker WETH balance and allowance
-        await web3Wrapper.awaitTransactionSuccessAsync(
-            await wethContract.deposit.sendTransactionAsync({
-                from: takerAddress,
-                value: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), DECIMALS_DEFAULT),
-            }),
-        );
-        await web3Wrapper.awaitTransactionSuccessAsync(
-            await wethContract.approve.sendTransactionAsync(
-                erc20Proxy.address,
-                constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
-                { from: takerAddress },
-            ),
-        );
-        web3Wrapper.abiDecoder.addABI(exchangeInstance.abi);
-        web3Wrapper.abiDecoder.addABI(zrxToken.abi);
-        erc20Wrapper.addTokenOwnerAddress(dutchAuctionContract.address);
-
-        currentBlockTimestamp = await getLatestBlockTimestampAsync();
-        // Default auction begins 10 minutes ago
-        auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp).minus(tenMinutesInSeconds);
-        // Default auction ends 10 from now
-        auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp).plus(tenMinutesInSeconds);
-        auctionBeginAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT);
-        auctionEndAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT);
-
-        // Default sell order and buy order are exact mirrors
-        const sellerDefaultOrderParams = {
-            salt: generatePseudoRandomSalt(),
-            exchangeAddress: exchangeInstance.address,
-            makerAddress,
-            feeRecipientAddress,
-            // taker address or sender address should be set to the ducth auction contract
-            takerAddress: dutchAuctionContract.address,
-            makerAssetData: DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
-                auctionBeginTimeSeconds,
-                auctionBeginAmount,
-            ),
-            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
-            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
-            takerAssetAmount: auctionEndAmount,
-            expirationTimeSeconds: auctionEndTimeSeconds,
-            makerFee: constants.ZERO_AMOUNT,
-            takerFee: constants.ZERO_AMOUNT,
-        };
-        // Default buy order is for the auction begin price
-        const buyerDefaultOrderParams = {
-            ...sellerDefaultOrderParams,
-            makerAddress: takerAddress,
-            makerAssetData: sellerDefaultOrderParams.takerAssetData,
-            takerAssetData: sellerDefaultOrderParams.makerAssetData,
-            makerAssetAmount: auctionBeginAmount,
-            takerAssetAmount: sellerDefaultOrderParams.makerAssetAmount,
-        };
-        const makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
-        const takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(takerAddress)];
-        sellerOrderFactory = new OrderFactory(makerPrivateKey, sellerDefaultOrderParams);
-        buyerOrderFactory = new OrderFactory(takerPrivateKey, buyerDefaultOrderParams);
-        defaultERC20MakerAssetData = assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress);
-    });
-    after(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-    beforeEach(async () => {
-        await blockchainLifecycle.startAsync();
-        erc20Balances = await erc20Wrapper.getBalancesAsync();
-        sellOrder = await sellerOrderFactory.newSignedOrderAsync();
-        buyOrder = await buyerOrderFactory.newSignedOrderAsync();
-    });
-    afterEach(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-    describe('matchOrders', () => {
-        it('should be worth the begin price at the begining of the auction', async () => {
-            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp + 2);
-            const makerAssetData = DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                defaultERC20MakerAssetData,
-                auctionBeginTimeSeconds,
-                auctionBeginAmount,
-            );
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({ makerAssetData });
-            const auctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            expect(auctionDetails.currentTimeSeconds).to.be.bignumber.lte(auctionBeginTimeSeconds);
-            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionBeginAmount);
-            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
-        });
-        it('should be be worth the end price at the end of the auction', async () => {
-            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
-            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
-            const makerAssetData = DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                defaultERC20MakerAssetData,
-                auctionBeginTimeSeconds,
-                auctionBeginAmount,
-            );
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                makerAssetData,
-                expirationTimeSeconds: auctionEndTimeSeconds,
-            });
-            const auctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            expect(auctionDetails.currentTimeSeconds).to.be.bignumber.gte(auctionEndTimeSeconds);
-            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionEndAmount);
-            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
-        });
-        it('should match orders at current amount and send excess to buyer', async () => {
-            const beforeAuctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
-                makerAssetAmount: beforeAuctionDetails.currentAmount.times(2),
-            });
-            await dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress);
-            const afterAuctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-            expect(newBalances[dutchAuctionContract.address][wethContract.address]).to.be.bignumber.equal(
-                constants.ZERO_AMOUNT,
-            );
-            // HACK gte used here due to a bug in ganache where the timestamp can change
-            // between multiple calls to the same block. Which can move the amount in our case
-            // ref: https://github.com/trufflesuite/ganache-core/issues/111
-            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
-                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
-            );
-            expect(newBalances[takerAddress][wethContract.address]).to.be.bignumber.gte(
-                erc20Balances[takerAddress][wethContract.address].minus(beforeAuctionDetails.currentAmount),
-            );
-        });
-        it('maker fees on sellOrder are paid to the fee receipient', async () => {
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                makerFee: new BigNumber(1),
-            });
-            await dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress);
-            const afterAuctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
-                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].plus(sellOrder.makerFee),
-            );
-        });
-        it('maker fees on buyOrder are paid to the fee receipient', async () => {
-            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
-                makerFee: new BigNumber(1),
-            });
-            await dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress);
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-            const afterAuctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
-                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].plus(buyOrder.makerFee),
-            );
-        });
-        it('should revert when auction expires', async () => {
-            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
-            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
-            const makerAssetData = DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                defaultERC20MakerAssetData,
-                auctionBeginTimeSeconds,
-                auctionBeginAmount,
-            );
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                expirationTimeSeconds: auctionEndTimeSeconds,
-                makerAssetData,
-            });
-            return expectTransactionFailedAsync(
-                dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress),
-                RevertReason.AuctionExpired,
-            );
-        });
-        it('cannot be filled for less than the current price', async () => {
-            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
-                makerAssetAmount: sellOrder.takerAssetAmount,
-            });
-            return expectTransactionFailedAsync(
-                dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress),
-                RevertReason.AuctionInvalidAmount,
-            );
-        });
-        it('auction begin amount must be higher than final amount ', async () => {
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                takerAssetAmount: auctionBeginAmount.plus(1),
-            });
-            return expectTransactionFailedAsync(
-                dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress),
-                RevertReason.AuctionInvalidAmount,
-            );
-        });
-        it('begin time is less than end time', async () => {
-            auctionBeginTimeSeconds = new BigNumber(auctionEndTimeSeconds).plus(tenMinutesInSeconds);
-            const makerAssetData = DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                defaultERC20MakerAssetData,
-                auctionBeginTimeSeconds,
-                auctionBeginAmount,
-            );
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                expirationTimeSeconds: auctionEndTimeSeconds,
-                makerAssetData,
-            });
-            return expectTransactionFailedAsync(
-                dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress),
-                RevertReason.AuctionInvalidBeginTime,
-            );
-        });
-        it('asset data contains auction parameters', async () => {
-            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
-            });
-            return expectTransactionFailedAsync(
-                dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress),
-                RevertReason.InvalidAssetData,
-            );
-        });
-
-        describe('ERC721', () => {
-            it('should match orders when ERC721', async () => {
-                const makerAssetId = erc721MakerAssetIds[0];
-                const erc721MakerAssetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId);
-                const makerAssetData = DutchAuctionWrapper.encodeDutchAuctionAssetData(
-                    erc721MakerAssetData,
-                    auctionBeginTimeSeconds,
-                    auctionBeginAmount,
-                );
-                sellOrder = await sellerOrderFactory.newSignedOrderAsync({
-                    makerAssetAmount: new BigNumber(1),
-                    makerAssetData,
-                });
-                buyOrder = await buyerOrderFactory.newSignedOrderAsync({
-                    takerAssetAmount: new BigNumber(1),
-                    takerAssetData: sellOrder.makerAssetData,
-                });
-                await dutchAuctionTestWrapper.matchOrdersAsync(buyOrder, sellOrder, takerAddress);
-                const afterAuctionDetails = await dutchAuctionTestWrapper.getAuctionDetailsAsync(sellOrder);
-                const newBalances = await erc20Wrapper.getBalancesAsync();
-                // HACK gte used here due to a bug in ganache where the timestamp can change
-                // between multiple calls to the same block. Which can move the amount in our case
-                // ref: https://github.com/trufflesuite/ganache-core/issues/111
-                expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
-                    erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
-                );
-                const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
-                expect(newOwner).to.be.bignumber.equal(takerAddress);
-            });
-        });
-    });
-});
--- a/Show More
+++ b/Show More