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tmux GHCI controller for Emacs
Emacs Lisp
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emamux-ghci is a small library wrapping emamux in-order to stream line usage of a tmux based GHCI session in Emacs. The primary features of emamux-ghci are file and buffer loading, plus management of include paths and language extension settings for the current loaded modules.


  • Shared Use of GHCI Between Editors

    Allows for the shared use of a single GHCI session by multiple editors (E.g. Emacs, Vim, Eclipse)

  • Separate GHCI to avoid dealing with process lock-ups in Emacs

  • Dodge Configuration Hell. Avoid broken hidden state machines in other plugins.

    This is useful as a hedge against a potential maintenance gap/shortfall for haskell-mode or inferior-haskell-mode. There is also still a need to use GHCI directly for its features such as color handling and completion, and that is somewhat of a moving target with respect to the rest of the Emacs ecosystem.

  • Test-Driven Development

    This is seeing regular use with Quickcheck's and HSpec's test runners, of which output terminal specific coloring and formatting for their results.



  • Emacs, tested with 24.4.2
  • tmux, tested with 1.3
  • emamux, tested with emamux-20141028
  • GHC & GHCI, tested with 7.10.1

Procedure: Just download emamux-ghci.el and drop it into an appropriate library load path, e.g. for /path/to/lib/:

(add-to-list 'load-path "~/path/to/lib/")
(require 'emamux-ghci)

Setup & Tips

Starting tmux

 $ tmux new-session -n ghci -s haskell 'cabal repl'

or with the following elisp:

   "-e" "tmux" "new-session" "-n" "ghci" "-s" "haskell" "cabal repl"

Tell emamux-ghci where to find the tmux session:

    ; Note, "haskell:ghci" is the default
    (setq emamux-ghci:tmux-address "haskell:ghci")

Add haskell module (or project) specific settings:

(setq emamux-ghci:includes '("src" "tests"))
(setq emamux-ghci:exts '("UnicodeSyntax" "GADTs"))

Note, a emamux-ghci:proj-sync is performed on emamux-ghci:proj-load-[buffer|file] if project settings have been changed. However, this can be done manually:

M-x emamux-ghci:proj-sync

Example keybindings (assuming use with haskell-mode):

(define-key haskell-mode-map [f2] 'emamux-ghci:proj-load-buffer)
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