bug#6935: 24.0.50; doc for `font-lock-maximum-decoration'

["Drew Adams" <drew.adams@oracle.com>]

> > This customization option lets users easily pick the level 
> > they want.  Just yesterday I had a user report about this
> > wrt Dired+ (my code had a bug that was preventing such a
> > choice).  Users have different needs
> > and preferences, and they do care about them.
> 
> 2 reasons:
> - rather than let people work around problems by reducing the 
>   level,

It's not a question of "working around" anything.  It's about providing levels
to give users a choice.

>   we should work harder to make sure that the default level is OK
>   for everyone.

That's silly.  If there is a _default_ level then there are level choices and a
notion of level.

No one disagrees that the default level should provide minimal fontification.
The point is to allow users to move to a higher level if they so wish.

> - "level" is the wrong way to think about this.  Instead, we 
>   should have separate controls for different font-lock features.

Be specific.  If you are agreeing that users should have choice and control when
it comes to the degree of font-locking, and you just disagree with the current
"level" mechanism, then propose something specific.

Note that in the case I cited the user had the ability to fine-tune
fontification, for example by customizing individual faces.  But he wanted a
coarse-grain control, to change the _level_.

That was so even though he was unaware of the current level mechanism.  He
sought a way to affect the level of fontification in one fell swoop.  And that's
just what the current level mechanism offers.

If you have a better way to give users that possibility, then please propose it
specifically (on emacs-devel).

I'd certainly agree that the current mechanism does not give users a way to
define the makeup of a given level themselves, and that that is a limitation.
The makeup of each level is hard-coded.  I, for one, would welcome a feature
that lets users (easily) define what each level should be.

That would likely mean letting them customize the font-lock keywords for each
level in some way.  And currently there is no good way for users to use
Customize to tailor a set of font-lock keywords.