Re: how to prevent font-lock from messing with a portion of text?

[Stefan Monnier <monnier@iro.umontreal.ca>]

> (defun put-text-property-unless-ignore (start end property value &optional
> object)
>   "`put-text-property', but ignore text with property `font-lock-ignore'."
>   (let ((here (min start end))
>         (end1 (max start end)))
>     (while (< here end1)
>       (unless (get-text-property here 'font-lock-ignore object)
>         (put-text-property here (1+ here) property value object))
>       (setq here (1+ here)))))

This will still override a face on a word inside a string, because
(get-text-property <string-start> 'font-lock-ignore object) will be nil.
You need to check for the presence of the property over the whole
start..end region.

> 2. In font-lock.el, use this definition of
> `font-lock-default-unfontify-region':

> (defun font-lock-default-unfontify-region (beg end)
>   "Unfontify from BEG to END, unless text with property `font-lock-ignore'."
>   (let ((here (min beg end))
>         (end1 (max beg end)))
>     (while (< here end1)
>       (unless (get-text-property here 'font-lock-ignore)
>         (remove-list-of-text-properties
>          here (1+ here) (append font-lock-extra-managed-props
>                                 (if font-lock-syntactic-keywords
>                                     '(syntax-table face font-lock-multiline)
>                                   '(face font-lock-multiline)))))
>       (setq here (1+ here)))))

Same thing here, except even more so.

Then the problem becomes that doing all those extra checks costs time, all
the time, for a feature which will be almost never used.

OK, here's another option: don't change anything to font-lock, don't fiddle
with it at all, just don't use text-properties to add your special faces.
Use overlays instead.
Problem solved,


        Stefan