lisp/progmodes/cmacexp.el

   1 ;;; cmacexp.el --- C macro expansion
   2
   3 ;; Maintainer: FSF
   4 ;; Last-Modified: 17 Apr 1992
   5 ;; Keywords: c
   6
   7 ;; Copyright (C) 1988 Free Software Foundation, Inc.
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Code:
  26
  27 (defvar c-macro-preprocessor "/lib/cpp"
  28   "*Command to be used for C preprocessing.")
  29
  30 (defvar c-macro-options nil
  31   "*List of options to use in C preprocessing.
  32 Each string in the list becomes a separate argument to the preprocessor.
  33 These arguments precede the filename.
  34 Use the `-I' option here to specify directories for header files.")
  35
  36 (defun c-macro-expand (beg end)
  37   "Display the result of expanding all C macros occurring in the region.
  38 The expansion is entirely correct because it uses the C preprocessor.
  39 You can use the variables `c-macro-preprocessor' and `c-macro-options'
  40 to customize how preprocessing is done, or specify header file directories
  41 and macros to predefine."
  42   (interactive "r")
  43   (let ((outbuf (get-buffer-create "*Macroexpansion*"))
  44         (tempfile "%%macroexpand%%")
  45         process
  46         last-needed)
  47     (save-excursion
  48       (set-buffer outbuf)
  49       (erase-buffer))
  50     (setq process (apply 'start-process "macros" outbuf c-macro-preprocessor
  51                          c-macro-options))
  52     (set-process-sentinel process '(lambda (&rest x)))
  53     (save-restriction
  54       (widen)
  55       (save-excursion
  56         (goto-char beg)
  57         (beginning-of-line)
  58         (setq last-needed (point))
  59         (if (re-search-backward "^[ \t]*#" nil t)
  60             (progn
  61               ;; Skip continued lines.
  62               (while (progn (end-of-line) (= (preceding-char) ?\\))
  63                 (forward-line 1))
  64               ;; Skip the last line of the macro definition we found.
  65               (forward-line 1)
  66               (setq last-needed (point)))))
  67       (write-region (point-min) last-needed tempfile nil 'nomsg)
  68       ;; Output comment ender in case last #-directive is inside a comment.
  69       ;; Also, terminate any string that we are in.
  70       (write-region "*//*\"*/\n" nil tempfile t 'nomsg)
  71       (write-region beg end (concat tempfile "x") nil 'nomsg)
  72       (process-send-string process (concat "#include \"" tempfile "\"\n"))
  73       (process-send-string process "\n")
  74       (process-send-string process (concat "#include \"" tempfile "x\"\n"))
  75       (process-send-eof process))
  76     (while (eq (process-status process) 'run)
  77       (accept-process-output))
  78     (delete-file tempfile)
  79     (delete-file (concat tempfile "x"))
  80     (display-buffer outbuf)
  81     (save-excursion
  82       (set-buffer outbuf)
  83       (goto-char (point-max))
  84       (forward-line -1)
  85       (delete-region (point) (point-max))
  86       (re-search-backward "\n# 1 ")
  87       (forward-line 2)
  88       (while (eolp) (delete-char 1))
  89       (delete-region (point-min) (point)))
  90     (display-buffer outbuf)))
  91
  92 ;;; cmacexp.el ends here