[luatex] How to get a \mid binary relation that grows in LuaTeX

[David Carlisle]

The same as plain tex to cut down the dependencies:-)


% https://tex.stackexchange.com/questions/401234/how-to-get-a-mid-binary-relation-that-grows-in-luatex

\tracingonline1
\showboxbreadth100
\scrollmode
\thickmuskip=10mu

$\left(a\mathrel{}\middle|\mathrel{}b\right)\showlists$\showlists

\bye


the math lists are similar in pdftex and luatex but the box output has
an extra empty box and an extra \thickuskip skip

David