Re: Proposal: Make StateT in mtl lazy

igloo:

http://hackage.haskell.org/trac/ghc/ticket/1127

Deadline: 28 February 2007.

I propose we make StateT lazy, as I suspect was the intention all along and as has been discussed (without reaching a conclusion) before.

The patch is simply (in the definition of (>>=)):

hunk ./Control/Monad/State.hs 195 - (a, s') <- runStateT m s + ~(a, s') <- runStateT m s

Is it possible to provide a short example of the different behaviours you need or expect? -- Don