Where is the data constructor for 'State'?

Question

After reading a couple of tutorials on Haskell state monads I wanted to try them out myself. The tutorials I read claim that the Control.Monad.State provide the following defini

Answer 1

A while ago the MTL switched from

newtype State s a = State ...

to

type State s = StateT s Identity

since otherwise we had to duplicate the logic for every monad and its transformer. Instead you can now use the state function

state :: (s -> (a, s)) -> State s a

Sadly, RWH and LYAH both are out of date in this respect :(