<..plain,latex math..>+
\:CheckOption{no-pmatrix} \if:Option \else
<.shared plain/latex pmatrix.>
\fi
-_-_-
<..shared plain/latex pmatrix..>
\def\:temp#1{\a:pmatrix\o:pmatrix:{#1}\b:pmatrix}
\HLet\pmatrix=\:temp
-_-_-
<..shared plain/latex pmatrix..>+
\NewConfigure{pmatrix}{2}
-_-_-