emacs major mode for Boost PropertyTree INFO file format and parser

info-mode.el

;;; info-mode-el -- Major mode for editing boost property tree INFO files.

;; Copyright (C) 2014 Roald Fernandez <[email protected]>

;; Author: Roald Fernandez <[email protected]>
;; URL: https://gist.github.com/swarminglogic/be3cd49fcba5ef891727
;; Created: 10 Nov 2014
;; Keywords: INFO major-mode

;; This program 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 2 of
;; the License, or (at your option) any later version.

;; This program 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 this program; if not, write to the Free
;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
;; MA 02111-1307 USA

;;; Commentary:

;; To use, place a copy of this file in your .emacs.d directory (for
;; example "~/.emacs.d/plugins"), and add the following to your .emacs
;; file:
;;
;;    (add-to-list 'load-path "~/.emacs.d/plugins/")
;;    (require 'generic-x)
;;    (require 'info-mode)
;;
;; This mode will automatically be enabled for file names "*.info"
;;
;; For more information about INFO files, see the boost property tree
;; documentation, chapter INFO parser:
;; http://www.boost.org/doc/libs/1_59_0/doc/html/property_tree/parsers.html


;;; Code:

(defvar info-indent-offset 4
  "Indentation offset for `info-mode'.")

(defun generic-indent-line ()
  "Indent current line for any balanced-paren-mode'."
  (interactive)
  (let ((indent-col 0)
        (indentation-increasers "[{]")
        (indentation-decreasers "[}]")
        )
    (save-excursion
      (beginning-of-line)
      (condition-case nil
          (while t
            (backward-up-list 1)
            (when (looking-at indentation-increasers)
              (setq indent-col (+ indent-col info-indent-offset))))
        (error nil)))
    (save-excursion
      (back-to-indentation)
      (when (and (looking-at indentation-decreasers) (>= indent-col info-indent-offset))
        (setq indent-col (- indent-col info-indent-offset))))
    (indent-line-to indent-col)))

;;;###autoload
(define-generic-mode 'info-mode
  '(";")
  '("true" "false")
  '(("^[ \t]*\\(#include\\)[ \t]+\\(\"[^\"]*?\"\\)"
     (1 font-lock-preprocessor-face)
     (2 font-lock-constant-face))
    ("^[ \t]*\\([^ \t\n\f{}]+\\)[ \t]*\\(?:$\\|{\\)"
     (1 font-lock-function-name-face))
    ("^[ \t]*\\([^ \t\n\f]+\\)[ \t]+\\(\"[^\"]*\"\\|[^{\\\" \t\f\n][^ \t\n\f]*\\)"
     (1 font-lock-variable-name-face)
     (2 font-lock-constant-face)))
  nil
  '((lambda ()
      (make-local-variable 'info-indent-offset)
      (make-local-variable 'generic-indent-line)
      (set 'indent-line-function 'generic-indent-line)
      ))
  "Major mode for boost property tree INFO files."
  )

;;;###autoload
(add-to-list 'auto-mode-alist (cons "\\.info\\'" 'info-mode))

(provide 'info-mode)

;;; info-mode.el ends here