module Ix(Ix(..)) where import CIx instance Ix Bool where range (c,c') = [c .. c'] index b@(c,c') ci | inRange b ci = fromEnum ci - fromEnum c | True = error "Ix.Bool.index: Index out of range." inRange (c,c') ci = c <= ci && ci <= c' -- Assuming Enum and Ord agree on order for Bool