Re: naming convention based file toggling facility

[Masatake YAMATO]

> I've had a hackish little elisp function for years that always struck me
> as a slightly surprising omission from emacs: the ability to toggle
> between files based on a naming convention like: <source>.c and
> <source>.h.

M-x ff-find-other-file may be useful.

I have another implementation.

Masatake YAMATO

;; c-alt.el --- Find header file or implementation file

;; Copyright (C) 2000 Masatake YAMATO

;; Author Masatake YAMATO <address@hidden>
;; Created: Tue Jun  4 17:00:22 1996
;; Time-stamp: <00/10/12 20:30:48 masata-y> 

;; This program 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 of the License, or
;; (at your option) any later version.
;; 
;; This program 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 this program; if not, write to the Free Software
;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

;; Commentary:
;; 
;; Put .emacs
;; 
;; (add-hook 'c-mode-hook (function (lambda () 
;;                            (define-key c-mode-map "\C-c\C-v" 
'c-find-alternative-file))))
;; (autoload 'c-find-alternative-file "c-alt" "Find .c or .h file" t)

;; Histroy
;; * Thu Oct 12 20:06:36 2000
;; Added c++ supports

(defun c-find-alternative-file (arg)
  "TODO"
  (interactive "P")
  (let* ((fname (buffer-file-name))
         (basename (file-name-sans-extension fname))
         (afname nil)
         (baselen (length basename))
         (ext (substring fname (1+ baselen))))
    (cond
     ((or (string= ext "c") (string= ext "m") (string= ext "cpp"))
      (setq afname (concat basename ".h"))
      (if (file-exists-p afname)
          (find-file afname)
        (if arg
            (find-file afname)
          (if (y-or-n-p (format "Cannot find! Create %s?: " afname))
              (find-file afname)
              ))
      ))
     ((string= ext "h")
      (if (or 
           (progn (setq afname (concat basename ".m")) (file-exists-p afname))
           (progn (setq afname (concat basename ".c")) (file-exists-p afname))
           (progn (setq afname (concat basename ".cpp")) (file-exists-p 
afname)))
          (find-file afname)
        (let ((newext (call-interactively 'c-get-alternative-file-name)))
          (setq afname (concat basename (cond 
                                         ((eq newext ?+)
                                          ".cpp")
                                         ((eq newext ?c)
                                          ".c")
                                         ((eq newext ?m)
                                          ".m")
                                         ((eq newext ?n)
                                          "")
                                         ((eq newext ?y)
                                          ".c")
                                         (t
                                          "")
                                         )))
          (if (not (eq newext ?n))
              (if (not (eq baselen (length afname)))
                  (find-file afname)
                (error "Wrong extension: %c" newext))))))
     (t
      (error "No alternative file for: %c" fname)))))

(defun c-get-alternative-file-name (ext)
  (interactive "cCannot find! Create?(type n(No) c(C), m(ObjC) or +(C++)): ")
  ext)
  
(provide 'c-alt)
;; c-alt.el ends here.