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

20 Mar 2021

      On Fri, Mar 19, 2021 at 9:49 AM Hans Hagen  wrote:
...
On 3/19/2021 4:58 AM, Christoph Reller wrote:
...
Hi,
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.
Is there anything I'm missing? (This could be a bug.)
not a bug, just the way tex works .. modes cannot know that what goes
into an argument is something verbose
but you can use this (also more efficient here):
\definetyping[T]
\definemode[mode][yes]
\starttext
\startmode[mode]
\startT
     Bla
\stopT
\stopmode
\stoptext
% there's also \startnotmode
Thank you for hinting at the environment form. The problem with this is,
that it cannot be nested, and that there is no "else" form.
E.g:

\startmode[A]
... mode A
\startmode[B]
... mode A and mode B
\elsemode
... mode A and not mode B
\stopmode
\stopmode

I know that there is \start(not)mode and \start(not)allmodes, but there
seems to be no way to use a general boolean expression such as:

\startmodes[A and not B]
...
\stopmodes

Of course we can do this in lua:

if tex.modes["A"] and not tex.modes{"B"] then
...
end

Keep up your excellent work! Cheers,

Christoph