Re: [NTG-context] Typing within doifmode leads to error

19 Mar 2021


      On Fri, Mar 19, 2021 at 5:38 AM Aditya Mahajan  wrote:
...
On Fri, 19 Mar 2021, Christoph Reller wrote:
...
Consider the following MWE:
\definetyping[T]
\definemode[mode][yes]
\starttext
\doifmode{mode}{%
  \startT
    Bla
  \stopT}
\stoptext
Compilation with the currently latest ConTeXt LMTX (ver: 2021.03.17 17:46
LMTX  fmt: 2021.3.18) fails with:
tex error       > runaway error: end of file encountered
mtx-context     | fatal error: return code: 1
Compilation is successful if I replace doifmode{mode}{...} by
\startmode[mode]...\stopmode.
Has to be with how tex works. The argument of any macro
(\doifmode{mode}{...} in this case) is scanned under the current catcode
regime. So, any environment (like typing) which changes catcodes does work
inside the argument to another macro.
I see. Strangely, the MWE did work in older versions of ConTeXt ;-)
...
So, either use the environment version of \doifmode (which doesn't
_capture_ it content):
\definetyping[T]
\definemode[mode][yes]
\starttext
\startmode[mode]
  \startT
    Bla
  \stopT
\stopmode
\stoptext
Or use buffers (to avoid catcode all together):
\definetyping[T]
\definemode[mode][yes]
\starttext
\startbuffer[code]
\startT
    Bla
\stopT
\stopbuffer
\doifmode{mode}{\getbuffer[code]}
\stoptext
or (note type**T**buffer so that the output is formatting according to the
options of \definetyping[T])
\definetyping[T]
\definemode[mode][yes]
\starttext
\startbuffer[code]
    Bla
\stopbuffer
\doifmode{mode}{\typeTbuffer[code]}
\stoptext
Perhaps this should be added to the FAQ on the wiki.
Aditya
Thank you for your ultra-speedy and very helpful response!

Christoph