IIRC that desugars to a >>= (\x -> b >>= (\y >>= return (f x y))) . I don't write Haskell, so that might be slightly off This could be doing any one of: - fla

IIRC that desugars to a >>= (\x -> b >>= (\y >>= return (f x y))) . I don't write Haskell, so that might be slightly off This could be doing any one of: - flatmapping over lists - doing a computation with Maybe types, producing Nothing if a or b are nothing - doing IO - managing futures - pretty much anything, actually Don't confuse 'x <- a' with assignment, or 'return' with returning a value. Another way of looking at it, (f x y) might be invoked: - once - never - more than once - later