This is the source code repository for Pact, a language for developing smart contracts to run on a fast deterministic blockchain.
The easiest way to try Pact is in the browser.
To start writing
smart contracts, the best way to go is to use the Atom editor and install
language-pact using the package manager.
You'll then need to install the Pact interpreter/REPL. On Mac, the easiest way to install pact is with Homebrew.
Make sure that Homebrew has been installed in your machine. Instructions for how to install it can be found here.
Once Homebrew is installed, run the following command to install pact:
brew install kadena-io/pact/pact
Pact can also be installed by following the instructions below:
- Install z3
- Download the prebuilt binaries for your distribution. Or see Building for instructions on how to build Pact from the source code.
- Once you've downloaded the binary, make sure that it is marked as executable by running
chmod +x <executable-file>. - Put the binary somewhere in your PATH.
For installing pact on Linux distributions in the Arch family, refer to this package on the AUR.
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.
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.
The REST API is documented at http://pact-language.readthedocs.io/en/latest/pact-reference.html#rest-api.
-
The pact-lang-api npm package provides a JavaScript library to aid interaction with the API.
-
The pact-todomvc is a working demonstration.
The HTTP server will host any static files it finds in its working directory.
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
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 Pact used to require 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.
NOTE: We are currently transitioning to Nix build infrastructure. Stack builds still work right now, but you should start transitioning to Nix using the instructions below.
- Go to https://nixos.org/nix/, click "Get Nix", follow the instructions to install the Nix package manager.
- Edit
$NIX_CONF_DIR/nix.conf.- Linux default:
/etc/nix/nix.conf
- Linux default:
- Set the
substitutersandtrusted-public-keyslines as follows:
substituters = https://pact.cachix.org https://nixcache.reflex-frp.org https://cache.nixos.org/
trusted-public-keys = pact.cachix.org-1:cg1bsryGrHnQzqEp52NcHq4mBBL+R25XbR2Q/I/vQ8Y= ryantrinkle.com-1:JJiAKaRv9mWgpVAz8dwewnZe0AzzEAzPkagE9SP5NWI= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
NOTE: In older versions of Nix, instead of substituters and
trusted-public-keys, use binary-caches and binary-cache-public-keys
respectively.
- If running Nix in multi-user mode (i.e. with a daemon), restart the Nix daemon.
On Mac:
sudo launchctl stop org.nixos.nix-daemon
sudo launchctl start org.nixos.nix-daemon
On Linux:
sudo systemctl restart nix-daemon.service
- Run
nix-buildfrom the project root.
Building with nix-build does a full rebuild every time, which is usually not
what you want when developing. To do incremental builds, you need to enter a nix
shell. To do that use the nix-shell command.
This puts you in a shell that has all the necessary dependencies installed. Once
inside this shell you can build as normal with cabal using cabal build or
cabal new-build.
You can also build with stack inside this shell as follows:
$ stack --stack-yaml stack-nix.yaml build
Nix has out-of-the-box Hoogle integration. It allows you to run a local Hoogle server with docs for all of the project dependencies. This is really nice for two reasons:
-
You know you're getting correct docs for the exact versions of the packages you are depending on.
-
You don't have to have an internet connection to access them.
To start the hoogle server, run this command from the project root directory.
nix-shell --run 'hoogle server --local'
This runs hoogle locally on port 8080. Running it this way, however, does not include haddocks for the pact (or whatever tho local project is). It only includes docs for the dependencies. To fix this, use the following command instead:
nix-shell -p 'with import ./. {}; ghc.ghcWithHoogle (p: [p.pact])' --run 'hoogle server --local'
To use the above command for other projects that use the .project
function
replace [p.pact] with a list of all the locally defined projects to include.
For example: [p.backend p.common p.frontend] for a project that has those
three separate local packages.
This code is distributed under the terms of the BSD3 license. See LICENSE for details.