Literate Haskell with Org Mode Documentation

haskell-org.el

;;; haskell-org.el --- Literate Haskell with Org Mode Documentation

;; Copyright (C) 2003, 2007  Free Software Foundation, Inc.
;; Authors: Dave Love <fx@gnu.org>
;; Keywords: languages, wp
;; Created: Sept 2003
;; $Revision: 1.5 $
;; URL: http://www.loveshack.ukfsn.org/emacs

;; Modified by Reetinder Sidhu on oct. 30, 2012 for org-mode support.
;; URL: http://sidhusblog.wordpress.com/2012/10/05/haskell-org/

;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This provides a mode for editing literate Haskell with the LaTeX
;; \begin{code}...\end{code} convention (but not the `Bird tracks'
;; `inverse comment' convention).
;; 
;; Thus you probably want to do something like this, assuming
;; haskell-latex is on `load-path' and $haskell_mode_path is the path
;; name of the haskell-latex directory:
;; 
;;   (load "$haskell_mode_path/haskell-site-file.el")
;;   (add-to-list 'auto-mode-alist '("\\.l[gh]s\\'" . haskell-latex-mode))
;;   (autoload 'haskell-latex-mode "haskell-latex")

;;; Code:

;; TODO: remove interactive, comments above, figure out autoload, auto
;; colorize when buffer visited, relabel haskorg as debug.

(require 'haskell-mode)
(require 'org-mode)
(require 'multi-mode)

(add-hook 'haskell-mode-hook (lambda () (setq haskell-literate 'bird)))

(add-hook 'org-mode-hook (lambda () (setq truncate-lines nil) (setq fill-column 79)))

(defun haskell-org-chunk-region (pos)
  "Determine type and limit of current chunk at POS.
Return (MODE START END), where MODE is `haskell-mode' or `org-mode'
and START and END are the limits of the chunk."
  (interactive)
  (save-excursion
    (save-restriction
      (widen)
      (goto-char pos)
	(beginning-of-line)
	(if (looking-at ">")
	    (haskell-org-search-extent 'haskell-mode "^[^>]")
	  (haskell-org-search-extent 'org-mode "^>")))))

(defun haskell-org-search-extent (mode regex)
"Determines start and end of chunk (either haskell or org)."
  (interactive)
  (progn (setq ppos (point))
	 (setq back (re-search-backward regex nil t))
	 (goto-char ppos)
	 (setq front (re-search-forward regex nil t))
	 (multi-make-list mode
			  (if back (progn (goto-char back) (forward-line) (point)) (point-min))
			  (if front (progn (goto-char front) (forward-line -1) (line-end-position)) (point-max)))))

;;;###autoload
(defun haskell-org-mode ()
  "Mode for editing `literate Haskell' with Org conventions."
  (interactive)
  (set (make-local-variable 'multi-alist)
       '((haskell-mode . haskell-org-chunk-region)
	 (org-mode . nil)))
  (multi-mode-install-modes))

(provide 'haskell-org)
;;; haskell-org.el ends here