Re: Fwd: Flymake and the 'face' property

["João Távora" <joaotavora@gmail.com>]

On Wed, Jan 30, 2019 at 3:41 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Stefan Monnier <monnier@iro.umontreal.ca>
> > Date: Wed, 30 Jan 2019 04:37:32 -0500
> >
> > > A 'face' property is documented for general use only for text, not for
> > > symbol plists.
> >
> > But the `category` text-property uses as text-properties the properties
> > of a symbol, so there is a real conflict in our current design.
>
> The 'category' symbols aren't faces, so there's no problem here.  the
> 'face' property has special meaning only on symbols that name a face.

Except when they are.  There is no rule in Emacs that says the same
symbol can't be used for multiple purposes. In fact, that is mostly the
Lisp way (functions, variables, fringe bitmaps, tests, etc, etc), at least
for the Lisps I'm familiar with.

So IMO it's not a trivial issue in neither theory or practice. Agreeing
with Stefan, if it's not too much trouble, I would like Emacs to not
violate this basic principle.

If it's not possible, then I think we must mention in the documentation
node about categories that 'face' is an obsolete alias for 'category-face'
(and add somewhere else that 'face', despite it's innocent-looking
name shouldn't be used at all).

João