Re: feature request: text property to prevent font-locking

[Wolfgang Jenkner <wjenkner@inode.at>]

On Thu, Aug 28 2014, Drew Adams wrote:

> I want to apply some ad-hoc highlighting with text property `face'
> in a font-locked buffer (whether font-locking occurs before or after
> I apply `face' for this highlighting).

> I do not want font-lock to override this highlighting.  I do not want
> to use `font-lock-keywords' (e.g. with KEEP) in order to create this
> highlighting.  I just want to prevent font-lock from overriding it.

So, let me try to understand the extent of the problem.

font-lock-default-unfontify-region leaves alone any "alternative"
(defined in char-property-alias-alist) of the `face' text property.

In particular, this is how the font-lock-face text property works.

Now, on the one hand, keyword fontification does not override
"alternatives" (except if the highlight pattern has an `override' flag).
This is because text-property-not-all recognizes them and thus prevents
font-lock-apply-highlight from adding a value for the `face' property.

On the other hand, some experimenting suggests that syntactic
fontification does override those "alternatives".

> I want to apply some other text property to the highlighted text,
> to tell font-lock not to fiddle with it ("hands off this text").

Remove it from the value of `font-lock-extra-managed-props'.

tl; dr: Existing facilities reduce the problem to clashes with syntactic
fontification.

Wolfgang