\starttext

    \ruledhbox{$\left|x\right|$}
    \ruledhbox{$\left(x\middle|x\right)$}

    \ruledhbox{$\startcheckedfences\left(x\leftorright|x\right)\stopcheckedfences$}
    \ruledhbox{$\startcheckedfences\leftorright|x\leftorright|\stopcheckedfences$}
    \ruledhbox{$\startcheckedfences\leftorright|x\stopcheckedfences$}

\stoptext
