Re: Execute lisp function on marked files

[Kevin Rodgers <ihs_4664@yahoo.com>]

Barney Dalton wrote:
 > This seems to do the trick, but I can't believe it doesn't already
 > exist. Comments on how to improve it would be welcomed.
 >
 > (defun dired-lisp-function (the-function)
 >   ;; Return nil for success, offending file name else.
 >   (let ((file (dired-get-filename)) failure)
 >     (condition-case err
 >         (funcall the-function file)
 >       (error (setq failure err)))
 >     (if (not failure)
 >         nil
 >       (dired-log "%s error for %s:\n%s\n" (symbol-name 'the-function)
 > file failure)
 >       (dired-make-relative file))))
 >
 >
 > (defun dired-do-lisp-function (the-function &optional arg)
 >   "Call THE-FUNCTION on each marked (or next ARG)
 >   files. THE-FUNCTION should take one argument (the filename)"
 >   (interactive "aFunction to apply to marked files : \nP")
 >   (dired-map-over-marks-check
 >    (function (lambda () (dired-lisp-function the-function)))
 >    arg
 >    (symbol-value 'the-function) t))

I think I would call them dired-funcall and dired-do-funcall, just name
the argument FUNCTION, make the doc string adhere to convention, and 
simplify
the call to dired-map-over-marks-check:

(defun dired-funcall (function)
   ;; Return nil for success, offending file name else.
   (let ((file (dired-get-filename)) failure)
     (condition-case err
         (funcall function file)
       (error (setq failure err)))
     (if (not failure)
         nil
       (dired-log "%s error for %s:\n%s\n" function file failure)
       (dired-make-relative file))))

(defun dired-do-funcall (function &optional arg)
   "Call FUNCTION on each marked (or next ARG) files.
FUNCTION should take one argument (the filename)."
   (interactive "aFunction to call on each marked file: \nP")
   (dired-map-over-marks-check (function dired-funcall) arg function t))

You might also consider restricting it to commands, which are a much
smaller set of functions that the user is more likely to be familiar
with:

   (interactive "CCommand ...")

-- 
Kevin Rodgers