Re: [Bug-AUCTeX] 11.82; xypic command crashes preview-latex

[David Kastrup]

Alexis Gallagher <address@hidden> writes:

> I have found that using the \xymatrix command from the xy-pic package
> crashes preview-latex. This is in contrast to merely not previewing
> correctly, a known issue discuessed on the mailing list in Jan 2006. The
> usual remedy, adding "delayed" as an optional argument to
> \usepackage{xy}, does not solve this problem.
>
> I enclose here a minimal example file, illustrating both the crasher,
> and the known older problem (substituing at signs with <at> to avoid
> antispam garbling):

Sorry for the delay in answering this.  I have checked in a fix into
CVS which makes your example make without any changes (or manually
loading preview).  The problem was that preview when used with the
textmath option changes the catcode of $ to active.  So that this gets
registered by XyMTeX (which was the fix for a previous problem),
\xyreuncatcodes gets called which records the catcodes of most
characters.  Unfortunately, at this point of time, a style file being
loaded, the catcode of @ is set to "letter", and this gets recorded as
well.  This means that \ar@, which usually would get interpreted as
\ar @, now calls the internal control sequence \ar@ instead of \ar
with @ following.

If you had separated \ar and @ with a space, this would likely have
worked.

Weird error.  I finally tracked it down by letting the stuff run with
\tracingall and with and without preview.sty, and diffing the log
files.

Then the difference between \ar@ and \ar @ became apparent.

Thanks for the report, and sorry for taking so long to reply.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum