default – Provide default parameters for TeX macros
The command \setdefault defines default values for the arguments of an existing macro; the macro, thus adjusted, is called with square brackets around arguments which are overriding the default. (This is the same scheme as is used in LaTeX.)
Maybe you are interested in the following packages as well.
- compare: Compare two strings
- ltxnew: A simple means of creating commands
- optparams: Macros with multiple optional parameters
- xnewcommand: Define \global and \protected commands with \newcommand