Set up Atom.io for developing Haskell on OS X

Posted on March 26, 2016

This is a step by step guide to setup Atom.io for developing Haskell on OS X (El Capitan). It highlights some extra configuration notes to avoid any issues I had today.

Screenshot

If you will finish all the steps you should be able to do write some fancy Haskell stuff with Atom.io like a Pro :-)

1. Preconditions

First of all we have to install ghc, which is the Glasgow Haskell Compiler and cabal as a package system for Haskell. We are using brew to install both on OS X as follow:

brew install ghc
brew install cabal-install

2. Install Cabal packages

Now we do need to install following cabal packages:

• happy is a parser generator for Haskell

cabal install happy

• ghc-mod is a backend program to enrich Haskell programming in editors.

cabal install ghc-mod

• stylish-haskell is a Haskell code prettifier.

cabal install stylish-haskell

3. Install and setup Atom packages

Finally we have to install all needed Atom packages by opening Atom -> Settings View -> Install Packages and Themes.

Please note: Some of following packages are depending on each other. That's why it is recommended to install all together.

If there a need of setting a custom configuration option it will be highlighted as custom configuration it the following list. After a package is installed You can set this custom option opening Atom -> Settings View -> Packages -> {your package} - Settings.

Ok, lets start to install and setup the following packages:

• ide-haskell Haskell IDE

# absolute path to stylish-haskell
"Stylish Haskell Path": /Users/{username}/.cabal/bin/stylish-haskell

If you are unsure what the path to stylish-haskell is, just check it as follow:

which stylish-haskell

• language-haskell Haskell language support in Atom

• ide-haskell-cabal Provides Cabal backend for ide-haskell

# version of GHC
"Active GHC version": 7.10

You can check your installed ghc version as follow:

ghc --version

It should be output something like this:

The Glorious Glasgow Haskell Compilation System, version 7.10.3

• autocomplete-haskell Autocomplete-plus provider for haskell

# name of the backend to use
"Use Backend": haskell-ghc-mod

• haskell-ghc-mod Provides backends for ide-haskell and autocomplete-haskell

# path to directory of cabal's binaries
"Additional Path Directories": /Users/{username}/.cabal/bin/

The location of cabal can be found by:

which cabal

• ide-haskell-repl Haskell REPL support for ide-haskell

# any REPL command, not needed by ghci
"Command Args": none
# path to ghci (GHC interpreter)
"Command Path": /usr/local/bin/ghci

To get the location of ghci just check it with:

which ghci

We are done! I hope you will have a nice Haskell running Atom editor right now :)

4. Questions?

If you have any questions or improvements, feel free to leave a comment or tweet to me @sectore

Have fun!

-Jens

Any feedback?