Re: [Haskell-cafe] Why are && and || right-associative?

I don't understand how laziness enters the picture:

(False && ⊥) && ⊥ ≡ False False && (⊥ && ⊥) ≡ False

in both cases we get the same result.

The first expression builds two thunks before trying the leftmost operand, and the second one only builds one thunk. More generally, a left-associative conjunction of n lazy Bools will build n - 1 thunks at once when forced, but a right-associative one will have only one at a time, though it may have to iterate through all n - 1 before finishing.