emacs/ppexpand.el

   1 ;;; ppexpand.el --- temporarily expanding macros in a pretty way.
   2
   3 ;; Copyright (C) 2000, 2006 Free Software Foundation, Inc.
   4
   5 ;;;; This library is free software; you can redistribute it and/or
   6 ;;;; modify it under the terms of the GNU Lesser General Public
   7 ;;;; License as published by the Free Software Foundation; either
   8 ;;;; version 3 of the License, or (at your option) any later version.
   9 ;;;;
  10 ;;;; This library is distributed in the hope that it will be useful,
  11 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 ;;;; Lesser General Public License for more details.
  14 ;;;;
  15 ;;;; You should have received a copy of the GNU Lesser General Public
  16 ;;;; License along with this library; if not, write to the Free
  17 ;;;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18 ;;;; 02111-1307 USA
  19
  20 ;;; Author: Mikael Djurfeldt <djurfeldt@nada.kth.se>
  21
  22 ;;; Commentary:
  23
  24 ;; Commands for editing multiline ANSI C compatible string literals.
  25
  26 ;;; Code:
  27 (require 'cmacexp)
  28
  29 (defvar if-mark "#if 0 /* PPEXPAND */")
  30 (defvar else-mark "#else /* PPEXPAND */")
  31 (defvar endif-mark "#endif /* PPEXPAND */")
  32
  33 (define-key c-mode-map "\C-ce" 'ppexpand)
  34
  35 (defun ppexpand (start end &optional undo)
  36   "Expand C macros in the region, using the C preprocessor.
  37 The expanded code is run through the `indent' command and inserted
  38 into the program next to the original code, using an #if/#else/#endif
  39 construct.
  40
  41 Given a prefix argument, it reverts the change, removing the
  42 #if/#else/#endif construct and the expanded code.
  43
  44 `c-macro-preprocessor' specifies the preprocessor to use.
  45 Prompt for arguments to the preprocessor \(e.g. `-DDEBUG -I ./include')
  46 if the user option `c-macro-prompt-flag' is non-nil.
  47
  48 Noninteractive args are START, END, UNDO.
  49 For use inside Lisp programs, see also `c-macro-expansion'."
  50
  51   (interactive (if current-prefix-arg
  52                    (list nil nil t)
  53                  (let ((pos1 (point))
  54                        (pos2 (mark)))
  55                    (if (< pos1 pos2)
  56                        (list pos1 pos2 nil)
  57                      (list pos2 pos1 nil)))))
  58   (let ((inbuf (current-buffer)))
  59     ;; Build the command string.
  60     (if c-macro-prompt-flag
  61         (setq c-macro-cppflags
  62               (read-string "Preprocessor arguments: "
  63                            c-macro-cppflags)))
  64     (if undo
  65         (let ((pos (point)) if-pos else-pos endif-pos)
  66           (save-excursion
  67             (end-of-line)
  68             (if (not (and (setq if-pos (search-backward if-mark nil t))
  69                           (setq else-pos (search-forward else-mark nil t))
  70                           (setq endif-pos (search-forward endif-mark nil t))
  71                           (<= if-pos pos)
  72                           (< pos endif-pos)))
  73                 (error "Not in ppexpanded region"))
  74             (let ((orig (buffer-substring (+ if-pos (length if-mark) 1)
  75                                           (- else-pos (length else-mark)))))
  76               (delete-region if-pos (+ endif-pos 1))
  77               (insert orig))))
  78       ;; Expand the macro.
  79       (let* ((expansion (c-macro-expansion start end
  80                                            (concat c-macro-preprocessor " "
  81                                                    c-macro-cppflags) t))
  82              (orig (buffer-substring start end)))
  83         (setq expansion
  84               (with-temp-buffer
  85                 (insert expansion)
  86                 (call-process-region (point-min) (point-max) "indent"
  87                                      t          ;delete the text
  88                                      t          ;output --> current buffer
  89                                      )
  90                 (buffer-string)))
  91         (delete-region start end)
  92         (insert if-mark ?\n orig else-mark ?\n expansion endif-mark ?\n)))))