bug#5105: 23.1; doc string of facemenu-set-face

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> > What?  Why are you arbitrarily deciding that?  Why not assume that
>> > allowing a string is a good thing, a purposeful design decision?
>> Because a good programmer knows that it's obviously not a good idea to
>> encourage the caller to use a string here.
> It might be obvious to what you call good programmers, but how about giving a
> _reason_, for us mere mortals?

How 'bout the other way around: give me a reason to accept strings.

>>> We have many places in Emacs where we allow an arg to be
>>> either a thing or its name.  Think of all of the BUFFER args
>>> that can be a buffer or a buffer name.
> What do the "good programmers" say about the design in those cases?  Is it
> "obviously not a good idea" also?

Very often, yes it's also a bad idea.  At least for buffers we have
a guarantee that there is a one-to-one mapping between (live) buffers
and buffer names, so for buffers it's a bit less bad.


        Stefan