swap by name

[VLD/VMB]

I'm not sure how one would implement a bind-by-reference
operator in a language with call-by-name function interface,
though.  Are the names to be forced through the bind or not?
I think my original statement is correct no matter what else
you add to the language, unless you break call-by-name.

In any case, I was just trying to illuminate one aspect of
the problem; you have added some more light to that.  Who
needs a universal swap macro anyway?