doomemacs/modules/lang/haskell/README.org

lang/haskell

• Table of Contents
• Description
  • External resources
  • Module Flags
  • Plugins
• Prerequisites
  • Cabal
    • MacOS
    • Arch Linux
    • openSUSE
  • LSP (haskell-language-server)
  • Stack
    • MacOS
    • Arch Linux
    • openSUSE
  • Haskell packages
• Configuration
  • Using the new-style cabal REPL
• Troubleshooting

Table of Contents   TOC

• Description

  • External resources
  • Module Flags
  • Plugins

• Prerequisites

  • Cabal
  • LSP (haskell-language-server)
  • Stack
  • Haskell packages

• Configuration

  • Using the new-style cabal REPL
• Troubleshooting

Description

This module adds Haskell support, powered by LSP (haskell-language-server).

• Code completion (company-ghc)
• Look up documentation (hoogle)
• REPL (ghci)
• Syntax-checking (flycheck)
• Snippets

External resources

Here are a few resources I've found indispensable in my Haskell adventures:

• Learn you a haskell for great good
• Haskell Programming from first principles
• Awesome Haskell: an extensive list of haskell resources
• The Haskell Tool Stack docs

Module Flags

• +lsp Enables LSP support with haskell-language-server (requires the :tools lsp module).

Plugins

• haskell-mode

• +lsp

  • lsp-haskell

Prerequisites

• LSP users need the haskell-language-server LSP server
• All users will need the hoogle package

Cabal

MacOS

brew install cabal-install ghc

Arch Linux

sudo pacman -S cabal-install ghc

openSUSE

sudo zypper install cabal-install ghc

LSP (haskell-language-server)

You will need stack and git installed.

You will find a comprehensive instructions for haskell-language-server on its project page, but if you are using ghcup:

ghcup install hls

Stack

To use LSP, you need stack:

MacOS

brew install haskell-stack
stack setup

Arch Linux

sudo pacman -S stack
# Replace pacaur with your AUR package manager of choice
pacaur -S ncurses5-compat-lib
stack setup

openSUSE

sudo zypper install stack
stack setup

Haskell packages

You'll need to install the following packages using stack or cabal:

• hoogle

  cabal update
  cabal install happy haskell-src-exts   # ghc-mod/hoogle dependencies
  cabal ghc-mod hoogle
  # or
  stack install ghc-mod
  stack install hoogle

And ensure the binaries for these packages are in your PATH, e.g.

# place this in your profile file, like ~/.bash_profile or ~/.zshenv
export PATH="~/.local/bin:$PATH"

Configuration

Using the new-style cabal REPL

haskell-mode will typically detect what REPL to run based on your project (e.g. stack, (old-style) cabal or ghc). If you want the new-style cabal REPL you must set haskell-process-type manually:

(setq haskell-process-type 'cabal-new-repl)

Troubleshooting

• Stack users: a dist/setup-config file in your project may cause ghc-mod to not work.