If I have a procedure:
procedure( foo( @key (x1 nil) )....)
And inside it I want to check to see if the key x1 was ever passed in, how would I do that?
I would want the behavior of:
to be different than
So what I need to check is whether x1 was passed in, not whether x1 == nil.
A local skill guru helped me out.
To check the existance of a variable being passed in, you just need to specify the variable as 'unbound and use a boundp check internally.
procedure( foo( @key (x1 'unbound)) if(boundp(x1) then .... ); if) ; procedure