RE: [Emacs-diffs] master 51e7e46: Font-lock elisp macros/special forms dynamically

[Drew Adams]

> Is it really a good idea to highlight *all* macros? Many are meant to be
> used just like functions and have the same semantics. Instead of
> updating a big macro regexp after load, there should be a `declare'
> attribute that would let specific macros (and functions) opt into being
> fontified specially.
> 
> As it is, I'm going to have to disable this functionality locally.

+1

Just what is this additional highlighting really trying to
accomplish?  What problem is it trying to fix?  Presumably this
corresponds to bug #20096, whose sole motivation was said to be:

"I like the addition of if-let and when-let in subr-x.el. However,
they should also be highlighted as keywords if subr-x is loaded."

To that "I like", the "fix" proposed by Stefan was: "change
elisp-mode's font-lock rules so they check obarray for macros",
and highlight them all.  As Stefan put it: "That should kill
several birds with a single (big) stone."

A big stone, indeed.  But what are the "several birds" that need
to be killed, and why?  No mention.

>From two unhighlighted macros that one user wants highlighted,
we've moved to highlighting all macros.  No discussion of the
why-do-this; discussion only of how-to-do-it.

If you must introduce such exhuberent highlighting, perhaps you
would consider throttling it via `font-lock-maximum-decoration'?

(And maybe consider highlighting only those two "I like" macros?)

Yes to Daniel's "let specific...opt into being fontified specially".

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20096