Rock that parses command lines?

[Dirk Laurie <dirk.laurie@...>]

Someone posted an announcement for a rock that takes your
help string and parses your command line. It turns 'args' into
a keyed table, e.g. {"-d", "s=specify"} --> {d=true, s="specify"}
and tests whether the option is documented.

This seems to be something that can neatly be done in pure Lua
but the only rock I could find is 'commandlineui' which seems to be
heavily system-dependent: e.g. it wants me to install GDBM.
I don't think that's the one I want.