The Pact Programming Language

This is the source code repository for Pact, a language for developing smart contracts to run on a fast deterministic blockchain.

References

Pact Homepage

Pact Reference Docs

Pact Whitepaper

Quick Start: Browser

The easiest way to try Pact is in the browser.

Quick Start: Atom

To start writing smart contracts, the best way to go is to use the Atom editor and install language-pact using the package manager.

Installing Pact with homebrew (OSX only)

You'll then need to install the Pact interpreter/REPL. On Mac, the easiest way is with homebrew.

brew install kadena-io/pact/pact

Installing Pact with Binary Distributions

Prebuilt binaries are available, or see building below.

Once you have downloaded the binary, put it somewhere in your PATH.

Verifying Install

Test by issuing pact in a terminal. Try out some commands:

$ pact
pact> (+ 1 2)
3
pact> (+ "hello, " "world")
"hello, world"

There are examples in this source repository of working smart contracts which you can load into Atom to get started.

Quick Start: Pact REST API Server

Pact now features a full REST API HTTP server and SQLite database implementation, making blockchain application development painless and easy. The Pact server simulates a single-node blockchain environment, with the same API supported by the Kadena ScalableBFT blockchain.

To start the server, issue pact --serve CONFIG or pact -s CONFIG, where CONFIG is a valid config.yaml.

REST API Docs

The REST API is documented at http://pact-language.readthedocs.io/en/latest/pact-reference.html#rest-api.

Related Projects

The pact-lang-api npm package provides a JavaScript library to aid interaction with the API.
The pact-todomvc is a working demonstration.

Hosting static files.

The HTTP server will host any static files it finds in its working directory.

Config file format

The pact dev server (pact-serve) requires a configuration Yaml file (e.g. server.conf) to operate. The documentation for it is:

➜  pact git:(feat/dev-server) pact --serve --help
Config file is YAML format with the following properties:
port       - HTTP server port
persistDir - Directory for database files.
             If ommitted, runs in-memory only.
logDir     - Directory for HTTP logs
pragmas    - SQLite pragmas to use with persistence DBs
verbose    - [True|False] Provide extra logging information

Replay from disk.

When running pact-serve with persistence enabled, the server automatically replays from the database commands.sqlite in the persist dir. To prevent replay, simply delete this file before starting the server.

Building

To build, you'll need a working Haskell Stack install . After which, building is as simple as 'stack build'.

To install for use with Atom and the command line, issue 'stack install' and then either add $HOME/.local/bin to your path, or symlink $HOME/.local/bin/pact somewhere in your PATH.

Building with GHCJS

To build pact for browser use, add --stack-yaml stack-ghcjs.yaml to your stack commands. The script web/build.sh builds Pact and minifies it; you'll need the closure compiler and a Java Runtime Environment installed.

License

This code is distributed under the terms of the BSD3 license. See LICENSE for details.

bts/pact