Latex syntax highlighting bug

[williamstein]

A user (of https://cloud.sagemath.com) reported to me that the syntax highlighting of the following two blocks should be identical in tex mode (text/x-stex), but they are not:

Block 1:

\begin{verbatim}
$foo
\end{verbatim}
blah

Block 2:

\begin{verbatim}
\$foo
\end{verbatim}
blah

It's easy to replicate this problem at http://codemirror.net/mode/stex/index.html

In practice this issue is quite serious because "blah" above could be pages of the rest of the document, and it all turns blue (say), when it shouldn't be.

I tested ACE (which is used by https://www.sharelatex.com) and it has a similar bug...

[marijnh]

TeX is a pretty horrible language to write editor modes for, since commands can define their own syntax, and there's no robust way to see, for example, which pieces of text are verbatim, and ignore commands in them. Just special-casing \begin{verbatim} isn't much of a solution (the various listing modules will all have a similar problem).

One kludge would be to disable math mode when a blank line is encountered. It wouldn't fix your example, but at least it'd prevent screwing up the highlighting of the whole remaining file in this situation. Does that sound like it'd help?

[williamstein]

Yes - that would be a major improvement.