David Green wrote:
I think I understand it... (my only quibble with the syntax is that === and eqv look like spin-offs of == and eq, but I don't know what to suggest instead (we're running short of combinations of = and : !))
Agreed.
So there are three basic kinds of comparison: whether the variables are the same (different names, but naming the same thing); whether the values are the same (deep comparison, i.e. recursively all the way down in the case of nested containers); and in-between (shallow comparison, i.e. we compare the top-level values, but we don't work out *their* values too, etc., the way a deep comparison would). If I've got it right, this is what =:=, eqv, and === give us, respectively.
Apparently, there are _four_ basic kinds of comparison: the ones mentioned above, and == (I believe that eq works enough like == that whatever can be said about one in relation to ===, =:=, or eqv can be said about the other). I'd be quite interested in an expansion of David's example to demonstrate how == differs from the others. -- Jonathan "Dataweaver" Lang
