Hello I am going through Walder's "Monads for Functional Programming" document. On page 9, there is a piece of code that provides the definition of return and bind for the State Monad I have pasted two variations of the code. The first one matches the definition given in the book. The second one is what I came up with. -- State Monad variation -- Retain the eval function as such -- Modify M , unit, * definitions type M a = State->(a, State) type State = Int unit :: a -> M a unit a = (\e->(a,e)) star :: M a -> (a -> M b) -> M b m `star` k = (\x -> let (a, aState) = m x in let (b, bState) = k a aState in (b, bState)) -- State Monad variation -- Retain the eval function as such -- Modify M , unit, * definitions type M a = State->(a, State) type State = Int unit :: a -> M a unit a = (\e->(a,e)) star :: M a -> (a -> M b) -> M b m `star` k = (\x -> let (a, aState) = m x (b, bState) = k a aState in (b, bState)) In the first definition of star, there are two let statements, while I found that one let statement would do the work anyway, as done in the second defintion of start I am not able to understand if there is any semantic implication in this syntatic variation of let. Please help. Thanks -- Regards Lakshmi Narasimhan T V