Posted by Kevin Chang on February 07, 2004 at 10:09:08:
In the lecture notes, because of contravariance we need the parity (flipping argument comparison). However, the P2 specification says that the types are {Int, Bool, Void, Interface}, all of which are disjoint in the lattice. For example Bool is not <= and not >= to anything else, Void is not <= and not >= to anything else, so on and so forth. There's no float/double/byte/etc. So is it correct to simply compare for "equals" and forget about parity?