> I'm a little unhappy with the grammar of it: > X1 and ... and Xn is T? > Shouldn't that be are_T(., ...)? I wish Erlang hadn't gone down the road of adding "is_" prefixes. After all, it's "length(L)" not "length_of(L)". But it's water under the bridge so we live with it. That said, the grammatical side of this doesn't bother me.