While learning about type classes, I tried to find the actual source code for Eq. In my beginner books this much is typically given
class Eq a where
(==), (/=) :: a -> a -> Bool
-- Minimal completion definition:
x /= y = not (x == y)
x == y = not (x /= y)
I then found
this at
hackage.haskell.org, but the "source" links are dead. On this page is a section of what I can't tell is either source code or just commentary on all the different mathematical ideas about equality, i.e.,
Reflexivity
x == x = True
Symmetry
x == y = y == x
Transitivity
if x == y && y == z = True, then x == z = True
Substitutivity
if x == y = True and f is a "public" function whose return type is an instance of Eq, then f x == f y = True
Negation
x /= y = not (x == y)
I would like to know if this is indeed in the source code or if it's just a sort of commentary. It looks important. Where can I find the actual source for all these basic type classes?
LB