Re: Execute lisp function on marked files

[Kevin Rodgers]

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