-- | Update the first component of a triple.
--
-- > first3 succ (1,1,1) == (2,1,1)
first3 :: (a -> a') -> (a, b, c) -> (a', b, c)
first3 f (a,b,c) = (f a,b,c)
first3 :: (a -> a') -> (a, b, c) -> (a', b, c)
first3 f (a,b,c) = (f a,b,c)
first3 f (a,b,c) = (f a,b,c)