On 13/08/2011 06:58, Dale Sedivec wrote:
>     Hi, I'm a MacTeX 2011 user.  I was working on a document that used
> expl3, then I decided to run the TeX Live Utility to update my
> installation.  After updating I could no longer build my document. After
> a lot of trial and error I think I've come up with a minimal example to
> demonstrate my problem:
> 
> ~~~~~~
> \documentclass{article}
> 
> \usepackage{expl3}
> 
> \ExplSyntaxNamesOn
> \ExplSyntaxNamesOff
> 
> \begin{document}
> 
> Colons break: boom!
> 
> \end{document}
> ~~~~~~
> 
>     Here are the errors I get when I run pdflatex over that:
> 
> ~~~~~~
> ! Missing $ inserted.
> <inserted text>
>                 $
> l.10 Colons break:
>                    boom!
> ! Missing $ inserted.
> <inserted text>
>                 $
> l.11
> ~~~~~~
> 
>     PRIOR to updating today, the $Id$ substitutions in my installation
> indicated I had something like expl3 from SVN revision 2246.  That
> revision worked fine with the above example.
> 
>     My newly-updated version of the LaTeX3 packages as well as the
> latest version from GitHub both produce the same errors as above.
> 
>     When I use \ExplSyntaxOff instead of \ExplSyntaxNamesOff, or if I
> copy in the definition for \ExplSyntaxNamesOff from r2246, the above
> code works.
> 
>     Is this my fault or is this a bug?
> 
> Thanks,
> Dale
> 

Hello David,

Thanks for the bug report: I've logged it as
https://github.com/latex3/svn-mirror/issues/39. This is a simple mix-up
in the code, as I managed to reverse ":" and "_" when setting category
codes. A fix will be checked in today, but it may be a few days before I
can update CTAN.
-- 
Joseph Wright