\starttext

\newdimen\mytexdimension \mytexdimension 100pt

\ruledhbox to\mytexdimension{\the\mytexdimension}

\ctxlua{document.myluadimension = "200pt"}

\ruledhbox to \cldcontext{document.myluadimension}{\cldcontext{document.myluadimension}}

\ctxlua{tex.dimen.mytexdimension = "300pt"}

\ruledhbox to\mytexdimension{\the\mytexdimension}

\stoptext
