The Haskell Tool Stack

stack is a cross-platform program for developing Haskell projects. It is aimed at Haskellers both new and experienced.

It features:

• Installing GHC automatically, in an isolated location.
• Installing packages needed for your project.
• Building your project.
• Testing your project.
• Benchmarking your project.

How to install

Downloads are available by operating system:

• Windows
• OS X
• Ubuntu
• Debian
• CentOS / Red Hat / Amazon Linux
• Fedora
• Arch Linux
• NixOS
• Linux (general)

Upgrade instructions

Note: if you are using cabal-install to install stack, you may need to pass a constraint to work around a Cabal issue: cabal install --constraint 'mono-traversable >= 0.9' stack.

Quick Start Guide

First you need to install it (see previous section).

Start your new project:

stack new my-project
cd my-project
stack setup
stack build
stack exec my-project-exe

• The stack new command will create a new directory containing all the needed files to start a project correctly.
• The stack setup will download the compiler if necessary in an isolated location (default ~/.stack) that won't interfere with any system-level installations. (For information on installation paths, please use the stack path command.).
• The stack build command will build the minimal project.
• stack exec my-project-exe will execute the command.
• If you just want to install an executable using stack, then all you have to do isstack install <package-name>.

If you want to launch a REPL:

stack ghci

Run stack for a complete list of commands.

Workflow

The stack new command should have created the following files:

.
├── LICENSE
├── Setup.hs
├── app
│   └── Main.hs
├── my-project.cabal
├── src
│   └── Lib.hs
├── stack.yaml
└── test
    └── Spec.hs

    3 directories, 7 files

So to manage your library:

1. Edit files in the src/ directory.

The app directory should preferably contains only files related to executables.

2. If you need to include another library (for example the package text:

   • Add the package text to the file my-project.cabal in the section build-depends: ....
   • run stack build another time

3. If you get an error that tells you your package isn't in the LTS. Just try to add a new version in the stack.yaml file in the extra-deps section.

It was a really fast introduction on how to start to code in Haskell using stack. If you want to go further, we highly recommend you to read the stack guide.

How to contribute

This assumes that you have already installed a version of stack, and have git installed.

1. Clone stack from git with git clone https://github.com/commercialhaskell/stack.git.
2. Enter into the stack folder with cd stack.
3. Build stack using a pre-existing stack install with stack setup && stack build.
4. Once stack finishes building, check the stack version with stack --version. Make sure the version is the latest.
5. Look for issues tagged with newcomer and awaiting-pr labels

Build from source as a one-liner:

git clone https://github.com/commercialhaskell/stack.git && \
cd stack && \
stack setup && \
stack build

Complete guide to stack

This repository also contains a complete user guide to using stack , covering all of the most common use cases.

Questions, Feedback, Discussion

• For frequently asked questions about detailed or specific use-cases, please see the FAQ.
• For general questions, comments, feedback and support please write to the stack mailing list.
• For bugs, issues, or requests please open an issue.
• When using Stack Overflow, please use the haskell-stack tag.

Why stack?

stack is a project of the Commercial Haskell group, spearheaded by FP Complete. It is designed to answer the needs of commercial Haskell users, hobbyist Haskellers, and individuals and companies thinking about starting to use Haskell. It is intended to be easy to use for newcomers, while providing the customizability and power experienced developers need.

While stack itself has been around since June of 2015, it is based on codebases used by FP Complete for its corporate customers and internally for years prior. stack is a refresh of that codebase combined with other open source efforts like stackage-cli to meet the needs of users everywhere.

A large impetus for the work on stack was a large survey of people interested in Haskell, which rated build issues as a major concern. The stack team hopes that stack can address these concerns.

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Documentation Table Of Contents

• Project Documentation
  • Maintainer Guide: includes releasing information
  • Signing Key: downloadable stack binaries are signed with this key
• Tool Documentation
  • Build Command: reference for the syntax of the build command and the command line targets
  • Dependency Visualization: uses Graphviz
  • Docker Integration
  • FAQ: frequently asked questions about detailed or specific use-cases
  • Install/Upgrade: a list of downloads available by operating system, installation instructions, and upgrade instructions
  • Nonstandard Project Initialization
  • Shell Autocompletion
  • User Guide: in-depth tutorial covering the most common use cases and all major stack features (requires no prior Haskell tooling experience)
  • YAML Configuration: reference for writing stack.yaml files
• Advanced Documentation
  • Architecture: reference for people curious about stack internals, wanting to get involved deeply in the codebase, or wanting to use stack in unusual ways