peg-mode.el

   1 ;;; peg-mode.el --- emacs mode for editing PEG grammar files
   2
   3 ;; Copyright (C) 2008  Free Software Foundation, Inc.
   4
   5 ;; Author: Utz-Uwe Haus <haus@juist.math.uni-magdeburg.de>
   6 ;; Keywords: data
   7
   8 ;; This file is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 2, or (at your option)
  11 ;; any later version.
  12
  13 ;; This file is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  20 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 ;; Boston, MA 02111-1307, USA.
  22
  23 ;;; Commentary:
  24 ;; This file provides a major mode for editing PEG grammar files.
  25 ;; It includes font-lock definitions and commands for
  26 ;; controlling indentation, re-indenting by subdivisions.
  27 ;;
  28 ;; To use, put the following in your .emacs:
  29 ;;
  30 ;; (autoload 'peg-mode "peg-mode" "Mode for editing PEG grammar files" t)
  31 ;;
  32 ;; You may also want something like:
  33 ;;
  34 ;; (setq auto-mode-alist
  35 ;;       (append '(("\\.peg$"    . peg-mode))
  36 ;;               auto-mode-alist))
  37
  38 ;;
  39
  40 ;;; Code:
  41 (defconst peg-version "0"
  42   "`peg-mode' version number.")
  43
  44 (require 'custom)
  45
  46 (defgroup peg nil
  47   "Support for editing PEG grammar files."
  48   :group 'languages)
  49
  50 (defcustom peg-mode-hook nil
  51   "*Hook to be run when `peg-mode' is entered."
  52   :type 'hook
  53   :group 'peg)
  54
  55 \f
  56 ;; Non-customizable
  57 (defconst peg-comment-re "#"
  58   "Regexp that starts a comment line.")
  59
  60
  61 ;; Utils
  62
  63
  64 ;; code
  65
  66
  67 ;; major-mode stuff
  68 (defvar peg-mode-abbrev-table nil
  69   "Abbreviation table used in `peg-mode' buffers.")
  70 (define-abbrev-table 'peg-mode-abbrev-table ())
  71
  72 (defvar peg-mode-syntax-table nil
  73   "Syntax table used in `peg-mode' buffers.")
  74 (if peg-mode-syntax-table
  75     nil
  76   (setq peg-mode-syntax-table (make-syntax-table)))
  77 (modify-syntax-entry ?#  "<"   peg-mode-syntax-table)
  78 (modify-syntax-entry ?\n ">"   peg-mode-syntax-table)
  79 (modify-syntax-entry ?(  "()"   peg-mode-syntax-table)
  80 (modify-syntax-entry ?[  "|"   peg-mode-syntax-table)
  81 (modify-syntax-entry ?]  "|"   peg-mode-syntax-table)
  82 (modify-syntax-entry ?\" "\""  peg-mode-syntax-table)
  83 (modify-syntax-entry ?'  "|"   peg-mode-syntax-table)
  84
  85
  86
  87 ;;;###autoload
  88 (defun  peg-mode ()
  89   "Major mode for editing xrdb config files"
  90   (interactive)
  91   (kill-all-local-variables)
  92   (set-syntax-table peg-mode-syntax-table)
  93   (setq major-mode 'peg-mode
  94         mode-name "peg"
  95         local-abbrev-table peg-mode-abbrev-table)
  96   ;(use-local-map peg-mode-map)
  97   (setq font-lock-defaults '(peg-font-lock-keywords))
  98   ;; local variables
  99   (make-local-variable 'parse-sexp-ignore-comments)
 100   (make-local-variable 'comment-start-skip)
 101   (make-local-variable 'comment-start)
 102   (make-local-variable 'comment-end)
 103   (make-local-variable 'paragraph-start)
 104   (make-local-variable 'paragraph-separate)
 105   (make-local-variable 'paragraph-ignore-fill-prefix)
 106   (make-local-variable 'indent-region-function)
 107   ;; now set their values
 108   (setq parse-sexp-ignore-comments t
 109         comment-start-skip "![ \t]*"
 110         comment-start "! "
 111         comment-end "")
 112   (setq indent-region-function 'peg-indent-region
 113         paragraph-ignore-fill-prefix t
 114         paragraph-start (concat "^[ \t]*$\\|^[ \t]*[!]\\|" page-delimiter)
 115         paragraph-separate paragraph-start)
 116   (run-hooks 'peg-mode-hook))
 117
 118 ;; faces and font-locking
 119 (defvar peg-rule-name-face 'peg-rule-name-face
 120   "Face for a production of a PEG rule's production in a peg grammar file.")
 121
 122
 123 (make-face 'peg-rule-name-face)
 124 ;(make-face 'xrdb-option-value-face)
 125
 126 (defun peg-font-lock-mode-hook ()
 127   (or (face-differs-from-default-p 'peg-rule-name-face)
 128       (copy-face 'font-lock-keyword-face 'peg-rule-name-face))
 129   (remove-hook 'font-lock-mode-hook 'peg-font-lock-mode-hook))
 130 (add-hook 'font-lock-mode-hook 'peg-font-lock-mode-hook)
 131
 132 (defvar peg-font-lock-keywords
 133   (list '("\\([^ \t\n]+\\)[ \t]*<-"
 134           (1 peg-rule-name-face))
 135         )
 136   "Additional expressions to highlight in peg grammar file mode.")
 137 (put 'peg-mode 'font-lock-defaults '(peg-font-lock-keywords))
 138
 139
 140 (provide 'peg-mode)
 141 ;;; peg-mode.el ends here