[Haskell] strict vs. lazy state threads

[Albert Lai]

Wolfgang Jeltsch <wolfgang at jeltsch.net> writes:

> The problem is that I cannot find an exact specification about what strict and 
> lazy means in conjunction with state threads.

This example shows a difference:

import Control.Monad.ST.Strict          -- try Lazy instead of Strict

example :: (forall s . ST s Int)
example = do
  undefined
  return 0

main = print (runST example)