(rmail-last-rmail-file): Initialize to a file name.
[bpt/emacs.git] / lisp / progmodes / cmacexp.el
1 ;;; cmacexp.el --- C preprocessor macro expansion
2
3 ;; Copyright (C) 1988 Free Software Foundation, Inc.
4
5 ;; Maintainer: FSF
6 ;; Keywords: c
7
8 ;; This file is part of GNU Emacs.
9
10 ;; GNU Emacs is free software; you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
13 ;; any later version.
14
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
19
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to
22 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
23
24 ;;; Commentary:
25
26 ;; This package gives you the ability to run the C macro preprocessor
27 ;; on the current region, expanding macros within it. This can be useful
28 ;; when you're not sure of the value or expansion of such macros and want
29 ;; to make sure they're doing what you think they're doing.
30 ;;
31 ;; This package supports the following option variables:
32 ;;
33 ;; c-macro-preprocessor --- program to be used for macro expansion.
34 ;; c-macro-options --- command-line options to pass it.
35
36 ;;; Code:
37
38 (defvar c-macro-preprocessor "/lib/cpp"
39 "*Command to be used for C preprocessing.")
40
41 (defvar c-macro-options nil
42 "*List of options to use in C preprocessing.
43 Each string in the list becomes a separate argument to the preprocessor.
44 These arguments precede the filename.
45 Use the `-I' option here to specify directories for header files.")
46
47 (defun c-macro-expand (beg end)
48 "Display the result of expanding all C macros occurring in the region.
49 The expansion is entirely correct because it uses the C preprocessor.
50 You can use the variables `c-macro-preprocessor' and `c-macro-options'
51 to customize how preprocessing is done, or specify header file directories
52 and macros to predefine."
53 (interactive "r")
54 (let ((outbuf (get-buffer-create "*Macroexpansion*"))
55 (tempfile "%%macroexpand%%")
56 expanded
57 process
58 last-needed)
59 (setq expanded (expand-file-name tempfile))
60 (save-excursion
61 (set-buffer outbuf)
62 (erase-buffer))
63 (setq process (apply 'start-process "macros" outbuf c-macro-preprocessor
64 c-macro-options))
65 (set-process-sentinel process '(lambda (&rest x)))
66 (save-restriction
67 (widen)
68 (save-excursion
69 (goto-char beg)
70 (beginning-of-line)
71 (setq last-needed (point))
72 (if (re-search-backward "^[ \t]*#" nil t)
73 (progn
74 ;; Skip continued lines.
75 (while (progn (end-of-line) (= (preceding-char) ?\\))
76 (forward-line 1))
77 ;; Skip the last line of the macro definition we found.
78 (forward-line 1)
79 (setq last-needed (point)))))
80 (write-region (point-min) last-needed expanded nil 'nomsg)
81 ;; Output comment ender in case last #-directive is inside a comment.
82 ;; Also, terminate any string that we are in.
83 (write-region "*//*\"*/\n" nil expanded t 'nomsg)
84 (write-region beg end (concat expanded "x") nil 'nomsg)
85 (process-send-string process (concat "#include \"" tempfile "\"\n"))
86 (process-send-string process "\n")
87 (process-send-string process (concat "#include \"" tempfile "x\"\n"))
88 (process-send-eof process)
89 ;; HPUX seems to want two eofs.
90 (process-send-eof process))
91 (while (eq (process-status process) 'run)
92 (accept-process-output))
93 (delete-file expanded)
94 (delete-file (concat expanded "x"))
95 (display-buffer outbuf)
96 (save-excursion
97 (set-buffer outbuf)
98 (goto-char (point-max))
99 (forward-line -1)
100 (delete-region (point) (point-max))
101 (re-search-backward "\n# 1 ")
102 (forward-line 2)
103 (while (eolp) (delete-char 1))
104 (delete-region (point-min) (point)))
105 (display-buffer outbuf)))
106
107 ;;; cmacexp.el ends here