[Haskell-beginners] State monad

Britt Anderson britt.uwaterloo at gmail.com
Mon Feb 14 19:11:19 CET 2011

Many of the tutorials on the state monad seem to suggest that you can use
State as a data constructor, but I can't get this to work. E.g. in ghci
after :m Control.Monad.State I can

let f = (\x -> (x,x))
let y = state f

but if I,

let z = State f

I get an error message: Not in scope: data constructor `State'.

Can someone please explain?

Thanks, Britt
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