# [NTG-context] Math letters in commands

Hans Hagen pragma at wxs.nl
Mon Sep 12 21:45:01 CEST 2016

On 9/12/2016 8:25 PM, Hans Åberg wrote:
> Found a workaround: The idea is to use \csname …\endcsname with two delimiters not likely to be used in math mode, below chosen to ‘…’.
>
> But then there seems to be a bug in the LuaTex \letcharcode command: There must be a character between “$” and the first occurring \activecatcode letter. Possibly this also causes a bug in \startformula, as discussed before. it's not a bug .. tex looks ahead for a second$ and in the process
expands  the next token which happens to be a letter at that point so it
gets injected as letter (it's the way tex works)

\appendtoks
\catcode𝐝\lettercatcode
\catcode𝐢\lettercatcode
\catcode𝐦\lettercatcode
\to \everymathematics

\definemathcommand[𝐝𝐢𝐦][nolop]{\mfunction{𝐦𝐢𝐝}}

\starttext

Note that $\𝐝𝐢𝐦 𝑉 = 𝖫$, although $\dim 𝑉 = 4$.

And a bug: $\𝐝𝐢𝐦 𝑉$.

\stoptext

fwiw, the current beta makes math characters also letters now

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