Re: Adding MIME viewers

[Hrvoje Niksic <hniksic@srce.hr>]

Robert Bihlmeyer <robbe@orcus.priv.at> writes:

> (defun mm-display-patch-inline (handle)
>   (let (text)
>     (with-temp-buffer
>       (mm-insert-part handle)
>       (diff-mode)
>       (font-lock-fontify-buffer)
>       (if (fboundp 'extent-list)
> 	  (mapc (lambda (el) (set-extent-property el 'duplicable t))
> 		(extent-list)))
>       (setq text (buffer-string)))
>     (mm-insert-inline handle text)))

mapc on the extent-list is a waste of resources -- use map-extents
instead.  Also, don't duplicate *all* the extents, but only the
relevant ones, say those with the `text-prop' property.  For instance:

(map-extents (lambda (ext ignored)
               (set-extent-property ext 'duplicable t)
               nil)
             nil nil nil nil nil 'text-prop)

(The above is untested.)

> Maybe this is really a misfeature of fontification, and the original
> version should work?

No, using nonduplicable properties is a feature, because normally we
*don't* want the colors to leak elsewhere.  font-lock uses the
text-properties interface because it comes more naturally than the
extents interface, not because of a need for automatic duplication.