lisp/progmodes/cmacexp.el

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