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Emacs for Haskell

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Literate programming

There are many Emacs packages and modules for Haskell. haskell-mode is stable and usable, whereas lsp-haskell is newer but under development and not ready for general use.

Newbie guide

Emacs is an extensible texteditor which can be extended with so-called "modes" and makes great use of keystrokes. Modes are written in Emacs Lisp (.el) programming language and provide additional commands and keystrokes. A mode is usually activated automatically via "hooks" based on file extensions (.hs, .cabal etc.) but can also be loaded during Emacs startup (~/.emacs) or in Emacs itself (enter: M-x haskell-mode). None of the modes listed below provide a complete out-of-the-box IDE; rather, each adds only a set of functionality specific to that mode. Note also that each mode must be installed separately. Lookup the specific help files to find out what each of them provide. To test if haskell-mode is actually installed type: M-x haskell-<tab>. You should get a list of commands. Entering "haskell-mode" provides additional commands. Try "haskell-version" for example.

Active projects

Haskell Language Server

The Haskell Language Server documentation contains instructions for:


spacemacs is an Emacs distribution.

It provides a Haskell development layer which integrates and combines many of the Emacs-Haskell-packages, like auto-completion from ghc-mod, linting, hoogle and more.


The haskell-mode package is a set of major modes for Emacs for writing Haskell code and working with Haskell projects. Features syntax highlighting, intelligent indentation, interaction with inferior Haskell interpreter, code browsing, and Cabal project integration. It support Hugs, GHCi, Cabal and hslint, hoogle, cabal-dev, and other utilities.

Haskell-mode is maintained by Philip Weaver. The official project is hosted on Github. For instructions on installing, see Installing haskell-mode. Issues should be reported to the Github project. Please state the version of Emacs and any relevant configuration, when writing your issue. There is a low traffic mailing list, too. Generally it is responsive to new posts.

Since 10th May 2014, there is extensive documentation for emacs haskell-mode on github.


lsp-haskell is a Language Server Protocol implementation for Haskell, which can interact with haskell-ide-engine.

tmux GHCI control

Emacs can also control a GHCI repl running in a tmux window. Libraries such as emamux-ghci have been written to simplify doing that.


haskell-emacs is a library which allows extending Emacs in Haskell. It provides an FFI (Foreign Function Interface) for Haskell functions.

Unsupported projects


No longer being updated

The Scion IDE library can be used to complement the haskell-mode with additional features, such as (quoting the documentation):

  • Highlights error messages directly in the source, together with a tool-tip
  • Optional on-the-fly typechecking (idle-time based, or whenever file is saved)
  • Completion on `LANGUAGE` names, pragmas, external module names and `OPTIONS`-flags
  • Go to definition sites of symbols at point

Documentation on how to use `scion.el` can be found in the `README.markdown` file.

The primary repository is at nominolo/scion. An experimental fork featuring GHC7 support can be found at hvr/scion.


No longer provides a supported IDE

"ghc-mod" is a backend command to enrich Haskell programming on editors including Emacs and Vim. The ghc-mod package on Hackage includes the "ghc-mod" command and Emacs front-end. Its source repository is on github.

Emacs front-end is an extension of Haskell mode. They enable to complete Haskell symbols on Emacs and to browse documents of modules. Flymake with GHC/Hlint is also integrated.

See the home page for more information.

Hugs mode

Alternative Hugs Mode for Emacs by Chris Van Humbeeck provides fontification and cooperation with Hugs. Updated for emacs 20.* by Adam P. Jenkins.