Arno Trautmann writes:
 > Hi,
 > I$,1ry(Bm looking for the possibility to define an optional argument like
 > \newcommand{\command}[2][default]{}
 > but didn$,1ry(Bt find anything. Is there no such thing or am I just too stupid
 > to find it? :(

on low-level, e.g. expl3 there is no point to provide something like optional
arguments, on a user interface level there is

   xparse     as a sample implementation a la latex2e

   template   for some design-level interface