16 Jun
2003
16 Jun
'03
8:58 a.m.
George Russell writes:
So what does the function insert2 val1 val2 = let (m1,k1) = insert empty (Just val1) (m2,k2) = insert m1 (Just val2) m3 = update m2 k1 Nothing in isJust (lookup m3 k2) return? It looks to me as if it returns True if val1 and val2 have different types, False if they have the same type. So you have now got a way of comparing two types for equality, and so a rather roundabout reimplementation of Dynamic.
I think I'm missing something... why is this? Do you only allow one value of each type? It seems to me that updating k1's value should not affect k2's. --KW 8-)