peg-mode.el

   1 ;;; peg-mode.el --- emacs mode for editing PEG grammar files
   2
   3 ;; Copyright (C) 2008  Utz-Uwe Haus <lisp@uuhaus.de>
   4
   5 ;; This file is free software; you can redistribute it and/or modify
   6 ;; it under the terms of the GNU General Public License as published by
   7 ;; the Free Software Foundation; either version 2, or (at your option)
   8 ;; any later version.
   9
  10 ;; This file is distributed in the hope that it will be useful,
  11 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ;; GNU General Public License for more details.
  14
  15 ;; You should have received a copy of the GNU General Public License
  16 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  17 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 ;; Boston, MA 02111-1307, USA.
  19
  20 ;;; Commentary:
  21 ;; This file provides a major mode for editing PEG grammar files.
  22 ;; It includes font-lock definitions and commands for
  23 ;; controlling indentation, re-indenting by subdivisions.
  24 ;;
  25 ;; To use, put the following in your .emacs:
  26 ;;
  27 ;; (autoload 'peg-mode "peg-mode" "Mode for editing PEG grammar files" t)
  28 ;;
  29 ;; You may also want something like:
  30 ;;
  31 ;; (setq auto-mode-alist
  32 ;;       (append '(("\\.peg$"    . peg-mode))
  33 ;;               auto-mode-alist))
  34
  35 ;;
  36
  37 ;;; Code:
  38 (defconst peg-version "0"
  39   "`peg-mode' version number.")
  40
  41 (require 'custom)
  42
  43 (defgroup peg nil
  44   "Support for editing PEG grammar files."
  45   :group 'languages)
  46
  47 (defcustom peg-mode-hook nil
  48   "*Hook to be run when `peg-mode' is entered."
  49   :type 'hook
  50   :group 'peg)
  51
  52 \f
  53 ;; Non-customizable
  54 (defconst peg-comment-re "#"
  55   "Regexp that starts a comment line.")
  56
  57
  58 ;; Utils
  59
  60
  61 ;; code
  62
  63
  64 ;; major-mode stuff
  65 (defvar peg-mode-abbrev-table nil
  66   "Abbreviation table used in `peg-mode' buffers.")
  67 (define-abbrev-table 'peg-mode-abbrev-table ())
  68
  69 (defvar peg-mode-syntax-table nil
  70   "Syntax table used in `peg-mode' buffers.")
  71 (if peg-mode-syntax-table
  72     nil
  73   (setq peg-mode-syntax-table (make-syntax-table)))
  74 ;; comments: starting at ', ending at end of line
  75 (modify-syntax-entry ?#  "<"   peg-mode-syntax-table)
  76 (modify-syntax-entry ?\n ">"   peg-mode-syntax-table)
  77 ;;  quoted strings
  78 (modify-syntax-entry ?\' "\""  peg-mode-syntax-table)
  79 (modify-syntax-entry ?\" "\""  peg-mode-syntax-table)
  80 ;; operators
  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 (modify-syntax-entry ?*  "."  peg-mode-syntax-table)
  85 (modify-syntax-entry ?/  "."  peg-mode-syntax-table)
  86 (modify-syntax-entry ?{  "<"  peg-mode-syntax-table)
  87 (modify-syntax-entry ?}  ">"  peg-mode-syntax-table)
  88 (modify-syntax-entry ?\\ "\\" peg-mode-syntax-table)
  89 ;;
  90 (modify-syntax-entry ?(  "()"   peg-mode-syntax-table)
  91 (modify-syntax-entry ?[  "|"   peg-mode-syntax-table)
  92 (modify-syntax-entry ?]  "|"   peg-mode-syntax-table)
  93 (modify-syntax-entry ?'  "|"   peg-mode-syntax-table)
  94
  95
  96
  97 ;;;###autoload
  98 (defun  peg-mode ()
  99   "Major mode for editing xrdb config files"
 100   (interactive)
 101   (kill-all-local-variables)
 102   (set-syntax-table peg-mode-syntax-table)
 103   (setq major-mode 'peg-mode
 104         mode-name "peg"
 105         local-abbrev-table peg-mode-abbrev-table)
 106   ;(use-local-map peg-mode-map)
 107   (setq font-lock-defaults '(peg-font-lock-keywords))
 108   ;; local variables
 109   (make-local-variable 'parse-sexp-ignore-comments)
 110   (make-local-variable 'comment-start-skip)
 111   (make-local-variable 'comment-start)
 112   (make-local-variable 'comment-end)
 113   (make-local-variable 'paragraph-start)
 114   (make-local-variable 'paragraph-separate)
 115   (make-local-variable 'paragraph-ignore-fill-prefix)
 116   (make-local-variable 'indent-region-function)
 117   ;; now set their values
 118   (setq parse-sexp-ignore-comments t
 119         comment-start-skip "![ \t]*"
 120         comment-start "! "
 121         comment-end "")
 122   (setq indent-region-function 'peg-indent-region
 123         paragraph-ignore-fill-prefix t
 124         paragraph-start (concat "^[ \t]*$\\|^[ \t]*[!]\\|" page-delimiter)
 125         paragraph-separate paragraph-start)
 126   (run-hooks 'peg-mode-hook))
 127
 128 ;; faces and font-locking
 129 (defvar peg-rule-name-face 'peg-rule-name-face
 130   "Face for a production of a PEG rule's production in a peg grammar file.")
 131
 132
 133 (make-face 'peg-rule-name-face)
 134 ;(make-face 'xrdb-option-value-face)
 135
 136 (defun peg-font-lock-mode-hook ()
 137   (or (face-differs-from-default-p 'peg-rule-name-face)
 138       (copy-face 'font-lock-keyword-face 'peg-rule-name-face))
 139   (remove-hook 'font-lock-mode-hook 'peg-font-lock-mode-hook))
 140 (add-hook 'font-lock-mode-hook 'peg-font-lock-mode-hook)
 141
 142 (defvar peg-font-lock-keywords
 143   (list '("\\([^ \t\n]+\\)[ \t]*<-"
 144           (1 peg-rule-name-face))
 145         )
 146   "Additional expressions to highlight in peg grammar file mode.")
 147 (put 'peg-mode 'font-lock-defaults '(peg-font-lock-keywords))
 148
 149
 150 (provide 'peg-mode)
 151 ;;; peg-mode.el ends here