Peter Verswyvelen-2 wrote:
I could try to read the article a couple of times again, but are there any other good readings about these existentially quantified types and how the ST monad works?
The primary source is if I'm not mistaken, the following "State in Haskell" paper: http://research.microsoft.com/en-us/um/people/simonpj/Papers/state-lasc.ps.g... Having said that, I'm not sure about the statement on page 9 that "readVar v simply does not have type forall s. ST s Bool." The variable v could be of type "forall s. MutVar s Bool", in which case all of "runST (readVar v)" typechecks. The sticking point really arises from "runST (newVar True)". So there isn't really "the other way round", but rather only one way. Am I misreading something? A minor nit, to be sure. -- View this message in context: http://www.nabble.com/forall---ST-monad-tp22024677p22026629.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.