Re: Macro Problem

[Pascal Bourguignon <pjb@informatimago.com>]

"vy" <volkan.yazici@gmail.com> writes:

> Hi,
>
> I'm trying to fix a macro for a simple task but still couldn't figure
> out the solution to the problem emacs complains about. Here's the
> related macro:
>
> (defun adhoc-make-font-face (face spec)
>   `(,face ((((class color)
>               (min-colors 8))
>              ,spec))))
>
> (defmacro adhoc-custom-set-faces (faces)
>   `(custom-set-faces
>     ,@(loop for face in faces
>             collect (adhoc-make-font-face (first face) (second
> face)))))

This will try to _execute_ the value returned by adhoc-make-font-face.
But a face is not a function, so adhoc-make-font-face should not
return a function call with face as a function, but a quoted list:

 (defun adhoc-make-font-face (face spec)
   `(quote (,face ((((class color)
                     (min-colors 8))
                    ,spec)))))

Of course you can write it as:
 (defun adhoc-make-font-face (face spec)
   `'(,face ((((class color)
                     (min-colors 8))
                    ,spec))))


Also, since adhoc-custom-set-face is a macro that doesn't evaluate its
argument, you shouldn't quote it.

(macroexpand '
 (adhoc-custom-set-faces
  ((font-lock-builtin-face (:foreground "yellow"))
    (font-lock-comment-face (:foreground "red"))
    (font-lock-function-name-face (:foreground "cyan"
                                   :underline "cyan"))))
)
-->
(custom-set-faces
 (quote (font-lock-builtin-face ((#1=((class color) (min-colors 8)) (:foreground "yellow")))))
 (quote (font-lock-comment-face ((#1# (:foreground "red")))))
 (quote (font-lock-function-name-face ((#1# (:foreground "cyan" :underline "cyan"))))))

And if you used (&rest faces) instead of (faces) for
adhoc-custom-set-faces, you could lose one parenthesis:

 (defmacro adhoc-custom-set-faces (&rest faces)
   `(custom-set-faces
     ,@(loop for face in faces
             collect (adhoc-make-font-face (first face) (second face)))))

(macroexpand '
 (adhoc-custom-set-faces
    (font-lock-builtin-face       (:foreground "yellow"))
    (font-lock-comment-face       (:foreground "red"))
    (font-lock-function-name-face (:foreground "cyan"
                                   :underline "cyan")))
)

--> 
(custom-set-faces
 (quote (font-lock-builtin-face ((#1=((class color) (min-colors 8)) (:foreground "yellow")))))
 (quote (font-lock-comment-face ((#1# (:foreground "red")))))
 (quote (font-lock-function-name-face ((#1# (:foreground "cyan" :underline "cyan"))))))



But since custom-set-faces is a function, perhaps you don't want
macros at all! In that case you don't need to return a quoted list
from adhoc-make-font-face, since you won't be trying to execute it:

(defun adhoc-make-font-face (face spec)
  `(,face ((((class color)
              (min-colors 8))
             ,spec))))

(defun adhoc-custom-set-faces (faces)
  (apply (function custom-set-faces)
     (loop for face in faces
           collect (adhoc-make-font-face (first face) (second face)))))


and then indeed you'd call it as:

 (adhoc-custom-set-faces
  '((font-lock-builtin-face (:foreground "yellow"))
    (font-lock-comment-face (:foreground "red"))
    (font-lock-function-name-face (:foreground "cyan"
                                   :underline "cyan"))))



> I'll be appreciated if anybody can give some hints about how to fix
> the problem.

So the problem was that for some strange reason you used defmacro
instead of defun. ;-)


-- 
__Pascal Bourguignon__
http://www.informatimago.com
http://pjb.ogamita.org