\verb work within...?
The LaTeX verbatim commands work by changing category codes. Knuth
says of this sort of thing ``Some care is needed to get the timing
right...'', since once the category code has been assigned to a
character, it doesn't change. So \verb has to assume that it is
getting the first look at its parameter text; if it isn't, TeX has
already assigned category codes so that \verb doesn't have a
chance. For example:
\verb+\error+
will work (typesetting `\error'), but
\newcommand{\unbrace}[1]{#1}
\unbrace{\verb+\error+}
will not (it will attempt to execute \error). Other errors one
may encounter are `\verb ended by end of line', or even `\verb
illegal in command argument'.
This is why the LaTeX book insists that verbatim
commands must not appear in the argument of any other command; they
aren't just fragile, they're quite unusable in any command parameter,
regardless of
\protection.