Measuring things

The first of these next commands was in LATEX 2.09. The two new commands are the obvious analogues.
\begin{decl}
\vert
\settowidth \vert \arg {length-cmd} \arg {lr text} \\
\vert
...
...lr text} \\
\vert
\settodepth \vert \arg {length-cmd} \arg {lr text}
\end{decl}