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emacs/lisp/progmodes/cmacexp.el
1993-03-22 03:27:18 +00:00

108 lines
3.9 KiB
EmacsLisp

;;; cmacexp.el --- C preprocessor macro expansion
;; Copyright (C) 1988 Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: c
;; This file is part of GNU Emacs.
;; GNU Emacs 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, or (at your option)
;; any later version.
;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;;; Commentary:
;; This package gives you the ability to run the C macro preprocessor
;; on the current region, expanding macros within it. This can be useful
;; when you're not sure of the value or expansion of such macros and want
;; to make sure they're doing what you think they're doing.
;;
;; This package supports the following option variables:
;;
;; c-macro-preprocessor --- program to be used for macro expansion.
;; c-macro-options --- command-line options to pass it.
;;; Code:
(defvar c-macro-preprocessor "/lib/cpp"
"*Command to be used for C preprocessing.")
(defvar c-macro-options nil
"*List of options to use in C preprocessing.
Each string in the list becomes a separate argument to the preprocessor.
These arguments precede the filename.
Use the `-I' option here to specify directories for header files.")
(defun c-macro-expand (beg end)
"Display the result of expanding all C macros occurring in the region.
The expansion is entirely correct because it uses the C preprocessor.
You can use the variables `c-macro-preprocessor' and `c-macro-options'
to customize how preprocessing is done, or specify header file directories
and macros to predefine."
(interactive "r")
(let ((outbuf (get-buffer-create "*Macroexpansion*"))
(tempfile "%%macroexpand%%")
expanded
process
last-needed)
(setq expanded (expand-file-name tempfile))
(save-excursion
(set-buffer outbuf)
(erase-buffer))
(setq process (apply 'start-process "macros" outbuf c-macro-preprocessor
c-macro-options))
(set-process-sentinel process '(lambda (&rest x)))
(save-restriction
(widen)
(save-excursion
(goto-char beg)
(beginning-of-line)
(setq last-needed (point))
(if (re-search-backward "^[ \t]*#" nil t)
(progn
;; Skip continued lines.
(while (progn (end-of-line) (= (preceding-char) ?\\))
(forward-line 1))
;; Skip the last line of the macro definition we found.
(forward-line 1)
(setq last-needed (point)))))
(write-region (point-min) last-needed expanded nil 'nomsg)
;; Output comment ender in case last #-directive is inside a comment.
;; Also, terminate any string that we are in.
(write-region "*//*\"*/\n" nil expanded t 'nomsg)
(write-region beg end (concat expanded "x") nil 'nomsg)
(process-send-string process (concat "#include \"" tempfile "\"\n"))
(process-send-string process "\n")
(process-send-string process (concat "#include \"" tempfile "x\"\n"))
(process-send-eof process)
;; HPUX seems to want two eofs.
(process-send-eof process))
(while (eq (process-status process) 'run)
(accept-process-output))
(delete-file expanded)
(delete-file (concat expanded "x"))
(display-buffer outbuf)
(save-excursion
(set-buffer outbuf)
(goto-char (point-max))
(forward-line -1)
(delete-region (point) (point-max))
(re-search-backward "\n# 1 ")
(forward-line 2)
(while (eolp) (delete-char 1))
(delete-region (point-min) (point)))
(display-buffer outbuf)))
;;; cmacexp.el ends here