[NTG-context] Bug with \wordright in LMTX version 2020-08-03 14:25

[Hans Hagen]

On 8/3/2020 10:10 PM, Otared Kavian wrote:
> Hi Hans,
> 
> A file which used to be typeset correctly with the previous versions of lmtx, now produces an error. Despite the error message being extremely cryptic:
> 
> Error	   ! Missing number, treated as zero
> 
> I could guess the origin of the bug, which seems to be \wordright,  but although the following minimal example shows a bug it does not produce the same ERROR output page:
> 
> %%%% the square ''end of proof''
> \definesymbol[Fin][\mathematics{\square}]
> \def\qed{\wordright{\symbol[Fin]}}
> 
> \starttext
> \startformula
> a^2 + b^2 = c^2
> \stopformula
> \qed % the problem is here
> \stoptext
> 
> In the above example if one adds something before \qed, then the square end-of-proof appears.
> However in my real file ConTeXt ouputs an error page and says: Error	   ! Missing number, treated as zero.
One can debate if the old behavior was ok ... wordright is meant for 
adding something at the end of a paragraph and you have none here. You 
can add a \strut in your definition to force a line.

The lmtx implementation actually permit this:

\definesymbol[Fin][\mathematics{\square}]
\def\qed{\strut\wordright{\symbol[Fin1]}\wordright{\symbol[Fin2]}\wordright{\symbol[Fin3]}}

\starttext
\startformula
a^2 + b^2 = c^2
\stopformula
\qed % the problem is here
\stoptext

i'm still exploring this but it has to do with collecting stuff, as in:

\wordright{before} test \par

test \wordright{before} \par

(i'll look at the number issue which indeed looks a like a bug)

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                                           Hans Hagen | PRAGMA ADE
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