[erlang-questions] setting up emacs for erlang

Mats Cronqvist <>
Thu Jan 25 17:00:56 CET 2007

   an emacs configured properly(1) is a pretty good IDE for erlang. it has 
smooth integration with the debugger, the erlang shell, the documentation etc.
   alas, getting it all to work is not particularly trivial.
   so please find enclosed a .emacs file that illustrates how it can be done(2).
   note that it assumes you've installed distel(3) and esense(4) first (which i 
highly recommend).


(1) where i define "properly" to mean "the way i like it"
(2) not done very well though; i'm a pretty lousy elisper
(3) jungerl.sourceforge.net
(4) esense.sourceforge.net

;; utility function to (brokenly :< ) handle versioned dirs
(defun wild (dir stem)
   "returns the last (alphabetically) filename that matches dir/stem*."
      (let (value)
        (dolist (element (file-name-all-completions stem dir) value)
	 (setq value (cons (concat dir element) value)))) 'string-lessp))))

;; we need to find the paths to OTP, distel and esense
;; for OTP, we need the dir containing man and lib.
;; on debian, that would be /usr/lib/erlang
;; for esense, we need the dir where esense.el lives
;; e.g. $HOME/code/esense-1.9
;; for distel, we need distel.el
;; e.g. $HOME/jungerl/lib/distel/elisp
;; you also need to add the corresponding bit to $HOME/.erlang
;; code:add_patha(os:getenv("HOME")++"/jungerl/lib/distel/ebin").

(defvar erlang-erl-path "/usr/lib/erlang")
(defvar erlang-esense-path (wild (concat (getenv "HOME") "/code/") "esense-"))
(defvar erlang-distel-path (concat (getenv "HOME") "/jungerl/lib/distel/elisp"))

;; hopefully no further configuration is needed

;; find the erlang mode .el file
(defvar erlang-erlmode-path
   (concat (wild (concat erlang-erl-path "/lib/") "tools-") "emacs"))

(add-to-list 'load-path erlang-erlmode-path)
(add-to-list 'load-path erlang-esense-path)
(add-to-list 'load-path erlang-distel-path)

(show-paren-mode t)
(global-font-lock-mode t)
(add-hook 'erlang-load-hook 'my-erlang-load-hook)

;; use to start an erlang shell with boot flags
(defun erl-shell (flags)
   "Start an erlang shell with flags"
   (interactive (list (read-string "Flags: ")))
   (set 'inferior-erlang-machine-options (split-string flags))

(defun my-erlang-load-hook ()
   (require 'distel)

   ;; when loading a beam file from emacs, add the path to erlang
   (setq erl-reload-dwim t)

   (require 'esense)
   (setq esense-indexer-program
	(concat erlang-esense-path "esense.sh"))
   (setq esense-completion-display-method 'frame)

   ;; find the man pages
   (setq erlang-root-dir erlang-erl-path))

(add-hook 'erlang-mode-hook 'my-erlang-mode-hook)
(defun my-erlang-mode-hook ()


   ;; distel The Right Way(tm)
   (local-set-key [(meta l)] 'erl-find-mod)
   (local-set-key [(meta \()] 'erl-openparent)
   (local-set-key [(meta /)]  'erl-complete)
   (local-set-key [(control x) (\?)] 'erlang-man-function)

   ;; make hack for compile command
   ;; uses Makefile if it exists, else looks for ../inc & ../ebin
   (unless (null buffer-file-name)
     (make-local-variable 'compile-command)
     (setq compile-command
           (if (file-exists-p "Makefile") "make -k"
	      "erlc "
	       (if (file-exists-p "../ebin") "-o ../ebin " "")
	       (if (file-exists-p "../inc") "-I ../inc " ""))
	      "+debug_info -W " buffer-file-name))))))

(add-hook 'comint-mode-hook 'my-comint)
(defun my-comint ()
   ;; try to make the shell more like the real shell
   (local-set-key [tab] 'comint-dynamic-complete)
   (local-set-key [(control up)] 'previous-line)
   (local-set-key [(control down)] 'next-line)
   (local-set-key [up] 'comint-previous-input)
   (local-set-key [down] 'comint-next-input))

(add-hook 'erlang-shell-mode-hook 'my-erlang-shell)
(defun my-erlang-shell ()
   (setq comint-dynamic-complete-functions
         '(my-erl-complete  comint-replace-by-expanded-history)))

(defun my-erl-complete ()
   "Call erl-complete if we have an Erlang node name"
   (if erl-nodename-cache
       (erl-complete erl-nodename-cache)

(require 'erlang-start)

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