Can a face have different attributes in different buffers?

Can a face have different attributes in different buffers?

[Yevgeniy Makarov]

Hello,

I have the following question. Judging by the fact that the function which
sets an attribute of some face (set-face-attribute) takes a frame as an
argument, it is not possible to have different buffers in one frame with
different values of the same attribute. Is it so? For example, can I have
comments of different colors (attribute :foreground of face
font-lock-comment-face) in different buffers of the same frame?

Thank you,
Yevgeniy

Re: Can a face have different attributes in different buffers?

[Pascal Bourguignon]

Yevgeniy Makarov <emakarov@cs.indiana.edu> writes:

> Hello,
> 
> I have the following question. Judging by the fact that the function which
> sets an attribute of some face (set-face-attribute) takes a frame as an
> argument, it is not possible to have different buffers in one frame with
> different values of the same attribute. Is it so? For example, can I have
> comments of different colors (attribute :foreground of face
> font-lock-comment-face) in different buffers of the same frame?

I don't think that's possible.  Faces are referenced thru
symbols. Ie. the way it is implemented, faces are not first class
objects, they're attributes of symbols.  Symbols aren't specific to a
buffer.

The best you could do is to create new faces for each buffer, copying
the faces you want onto new gensym'ed symbols and refering them thru
buffer-local  variables.  Of course, since normal font-locking code
refers the faces "literally" thru the symbols they use, you'd have to
patch them or program your own font-locking.


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
The mighty hunter
Returns with gifts of plump birds,
Your foot just squashed one.

Re: Can a face have different attributes in different buffers?

[Johan Bockgård]

Pascal Bourguignon <spam@mouse-potato.com> writes:

> I don't think that's possible. Faces are referenced thru symbols.

The standard font lock faces are referenced through variables.

C-h v font-lock-comment-face RET =>

    font-lock-comment-face's value is 
    font-lock-comment-face

    Face name to use for comments.

    Defined in `font-lock'.


> Of course, since normal font-locking code refers the faces
> "literally" thru the symbols they use, you'd have to patch them or
> program your own font-locking.

It doesn't, though.

-- 
Johan Bockgård

Re: Can a face have different attributes in different buffers?

[Yevgeniy Makarov]

Johan Bockgård wrote:

> The standard font lock faces are referenced through variables.

That's a great idea. I created a new face called mail-quotation-face after the
example of font-lock-comment-face, and then put the following code in .emacs:

(add-hook 'mail-mode-hook
  '(lambda ()
     (make-local-variable 'font-lock-comment-face)
     (setq font-lock-comment-face 'mail-quotation-face)))

This makes quotation one color, and the comments in other buffers are another
color.

Thank you again,
Yevgeniy

Re: Can a face have different attributes in different buffers?

[Kevin Rodgers]

Yevgeniy Makarov wrote:
 > (add-hook 'mail-mode-hook
 >   '(lambda ()
 >      (make-local-variable 'font-lock-comment-face)
 >      (setq font-lock-comment-face 'mail-quotation-face)))

FYI, that can be shortened to

(add-hook 'mail-mode-hook
           (lambda ()
             (set (make-local-variable 'font-lock-comment-face)
                  'mail-quotation-face)))

-- 
Kevin Rodgers