Re: make-glyph-code incompatibility

[Eli Zaretskii]

> From: address@hidden (Kim F. Storm)
> Date: Tue, 04 Mar 2008 01:08:22 +0100
> Cc: address@hidden
> 
> Stefan Monnier <address@hidden> writes:
> 
> > The new make-glyph-code is a good change, but it introduces
> > an incompatibility.  It seems that it makes previously working code
> > fail silently.  Can we make it fail with an informative message?
> 
> For example, how do you differentiate
> 
>     1 << 19 + ?a    (emacs 22 glyph code for 'a' in mode-line face)
> 
> and the unicode character with the same numeric value in emacs 23 ?
> 
> Also, issuing warnings during redisplay is a mess!

Yes.  But you could make the new code use different symbols, and make
old symbols be unbound.  That would cause error messages early enough.