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.
- defstring: Define macros as verbatim macros
- balancedquotes: Code balanced quotes according to document language
- patch: Patch loaded packages, etc
- styledcmd: Handling multiple versions of user-defined macros