Re: using glyphs by default in perl-mode

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

> 1) move `perl--prettify-symbols-alist' and the functions for it,
> `perl--font-lock-compose-symbol' and `perl--font-lock-symbols-keywords'
> to simple.el (with the "prog-" prefix).

You might like to consider the pretty-lambda for Lisp as well as the
sml-font-lock-symbols in elpa/packages/sml-mode/sml-mode.el.
[ There are others out there for, e.g. for Hasekll-mode.  ]

> 2) declare `perl-prettify-symbols' obsolete in favor of the alist
> `prog-prettify-symbols'.

No need for such obsolescence declaration, since it's never been in any
released version.

> I gave `prog-prettify-symbols' two default choices:
> `prog--prettify-symbols-alist-basic' (just -> => ::) and
> `prog--prettify-symbols-alist-extended' (basic plus much more).  It can
> also be a free-form alist with key=string, value=character.  I expect
> programming modes will need to augment this list somehow, but I'd like
> the user to simply say "I want basics or extended" instead of having to
> select individual glyphs for every language.  Maybe the choice should be
> between :basic and :extended as symbols?  Ideas welcome.

In my experience, every major mode might want to provide its own list.

> The patch grows simple.el.  Perhaps it should live in prog.el or
> prettify.el.  prog.el seems more sensible.

I think prog-mode.el is in order, yes.

> I also wonder if it's possible to add the prettify support at the
> `prog-mode' level, so each mode doesn't have to explicitly inline
> those keywords.

That would be nice, indeed.  But I fear it's going to be tricky to make
it work right, so let's keep it for later.

> Unfortunately my font-lock-fu is not good, so I'd really appreciate help
> with the last two issues.  I spent a few hours on them but couldn't work
> them out.

I don't have much time to devote right now, but the current problem is
probably a minor oversight.


        Stefan