Re: modify-syntax-entry and UTF8?

[Geoffrey Alan Washburn <geoffw@cis.upenn.edu>]

James Cloos wrote:
>>>>>> "Geoffrey" == Geoffrey Alan Washburn <geoffw@cis.upenn.edu> writes:
> 
> Geoffrey> No, what I wrote is exactly what I meant, unless the author of
> Geoffrey> the TeX-input method incorrectly defined \langle and \rangle.
> 
> Ah.  That does put a different spin on things.
> 
> And in fact, the UCS has expanded since that was written, and characters
> were added for exactly TeX's \langle and \rlangle (and a few others in
> latin-ltx.el which currently point to CJK characters instead of math chars).
> 
> latin-ltx.el should be updated to use ⟨ U+27E8 MATHEMATICAL LEFT ANGLE
> BRACKET for \langle and ⟩ U+27E9 MATHEMATICAL RIGHT ANGLE BRACKET for \rangle.

Ah, that is good to know.  Is there any straightforward way to override 
this in my .emacs file?

> What does C-uC-x= output when point is on the characters in your
> (modify-syntax-entry) calls and when point is on one of the characters
> you are trying to match in the buffer you are editing?  What are the
> mode and coding-system of the buffer you are editing?  What is the
> coding-system of the .el file?

So when using the correct glyphs I get

         character: ⟨ (10216, #o23750, #x27e8)
preferred charset: unicode (Unicode (ISO10646))
        code point: 0x27E8
            syntax: (⟩	which means: open, matches ⟩
       buffer code: #xE2 #x9F #xA8
         file code: #xE2 #x9F #xA8 (encoded by coding system utf-8-unix)
           display: no font available
...

and

         character: ⟩ (10217, #o23751, #x27e9)
preferred charset: unicode (Unicode (ISO10646))
        code point: 0x27E9
            syntax: )⟨	which means: close, matches ⟨
       buffer code: #xE2 #x9F #xA9
         file code: #xE2 #x9F #xA9 (encoded by coding system utf-8-unix)
           display: no font available

...

which as I understand it means that they should already be treated as 
matching delimiters.

However, if create an empty scratch buffer and I move the cursor on top 
of either of the glyphs they become highlighted, but with the face that 
is used for matched delimiters rather than the face mismatch/unmatched 
delimiters.  Adding both glyphs to an empty buffer in correctly and 
incorrectly matching permutations gives the same behavior.

So I am inclined to believe Stefan's hypothesis that modify-syntax-entry 
is working correctly here and instead whatever code actually interprets 
the syntax table or performs the actual adjustment to the faces for 
highlighting has a bug of some sort.

I'm also somewhat curious that emacs tells me that no font is available 
for these glyphs, but Thunderbird seems to be able to locate a font that 
can be used to display them.