Contracts for Compact

A library for secure smart contract development written in Compact for Midnight. This library consists of modules to build custom smart contracts.

This repo contains highly experimental code. Expect rapid iteration. Use at your own risk.

Usage

Make sure you have nvm and yarn installed on your machine.

Follow Midnight’s Compact Developer Tools installation guide and confirm that compact is in the PATH env variable.

$ compact compile --version

Compactc version: 0.26.0
0.26.0

Installation

Create a directory for your project.

mkdir my-project
cd my-project

Initialize git and add OpenZeppelin Contracts for Compact as a submodule.

git init && \
git submodule add https://github.com/OpenZeppelin/compact-contracts.git

cd into it and then install dependencies and prepare the environment.

nvm install && \
yarn && \
SKIP_ZK=true yarn compact

Write a custom contract using library modules

In the root of my-project, create a custom contract using OpenZeppelin Compact modules. Import the modules through compact-contracts/node_modules/@openzeppelin-compact/contracts/…​. Import modules through node_modules rather than directly to avoid state conflicts between shared dependencies.

Installing the library will be easier once it’s available as an NPM package. 
// MyContract.compact

pragma language_version >= 0.16.0;

import CompactStandardLibrary;
import "./compact-contracts/node_modules/@openzeppelin-compact/contracts/src/access/Ownable"
  prefix Ownable_;
import "./compact-contracts/node_modules/@openzeppelin-compact/contracts/src/security/Pausable"
  prefix Pausable_;
import "./compact-contracts/node_modules/@openzeppelin-compact/contracts/src/token/FungibleToken"
  prefix FungibleToken_;

constructor(
  _name: Opaque<"string">,
  _symbol: Opaque<"string">,
  _decimals: Uint<8>,
  _recipient: Either<ZswapCoinPublicKey, ContractAddress>,
  _amount: Uint<128>,
  _initOwner: Either<ZswapCoinPublicKey, ContractAddress>,
) {
  Ownable_initialize(_initOwner);
  FungibleToken_initialize(_name, _symbol, _decimals);
  FungibleToken__mint(_recipient, _amount);
}

export circuit transfer(
  to: Either<ZswapCoinPublicKey, ContractAddress>,
  value: Uint<128>,
): Boolean {
  Pausable_assertNotPaused();
  return FungibleToken_transfer(to, value);
}

export circuit pause(): [] {
  Ownable_assertOnlyOwner();
  Pausable__pause();
}

export circuit unpause(): [] {
  Ownable_assertOnlyOwner();
  Pausable__unpause();
}

(...)

Compile the contract

In the project root, compile the contract using Compact’s dev tools.

% compact compile MyContract.compact artifacts/MyContract
Compiling 3 circuits:
  circuit "pause" (k=10, rows=125)
  circuit "transfer" (k=11, rows=1180)
  circuit "unpause" (k=10, rows=121)
Overall progress [====================] 3/3
ZK Circuits 101 →