> Aditya Mahajan <mailto:adityam@umich.edu>
> 22. Oktober 2015 um 02:52
> Hi,
>
> The following example fails:
>
> \usemodule[pgfplots]
> \usepgfplotslibrary[fillbetween]
>
> \starttext
> \startformula
>   \left. a \right|
> \stopformula
>
> \stoptext
>
> with
>
> tex error > tex error on line 7 in file /private/tmp/test.tex: ! 
> Missing \endgroup inserted
>
> <inserted text>
> \endgroup
> <to be read again>
> \Ucheckedstopdisplaymath
> \stopdisplaymath ...math \Ucheckedstopdisplaymath
>                                                   \par \ifvmode 
> \ifcase \c_s...
> \strc_formulas_stop_formula ...native \v!formula }
>                                                   \dostoptagged 
> \dostoptagge...
> l.7 \stopformula
>
> This is a weird bug. Only \left. \right| fails; \left| \right| works 
> correctly. If I remove the fillbetween library, the error goes away.
>
> Any hints as to what is happening will be appreciated.

The fillbetween library changes the catcode of the bar character.

\starttext

\the\catcode`|

\usemodule[pgfplots]
\usepgfplotslibrary[fillbetween]

\the\catcode`|

\stoptext


You get the same error when you use \asciimode in your document.

\asciimode

\starttext

\startformula
   \left. a \right|
\stopformula

\stoptext


Wolfgang