[tex-eplain] Definition with an optional argument

[Rodolfo Medina]

Hi all.

In a certain two-argument definition, I wish that the second argument was
optional, i.e. if it's not there it is like it didn't exist at all in the
definition.

I don't understand well the use of \@getoptionalarg and \@optionalarg as
explained in eplain manual.

Can anybody please provide a clearer example of how I can make one of my two
arguments optional using \@getoptionalarg and \@optionalarg?

Thanks for any help
Rodolfo