Hello,
The following test-file produces an error:
% engine=luatex
\usemodule[chemic]
\starttext
\chemical{CO_2}
\stoptext
ERROR: Undefined control sequence.
--- TeX said ---
<argument> \s
!chemical\c !x1
\setvalue #1->\expandafter \def \csname #1
\endcsname
l.2067 \setvalue{\s!chemical\c!x1}
{0}
Cheers, Peter
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