[Haskell-cafe] primitive operations in StateT
cgaebel at uwaterloo.ca
Tue Apr 16 07:56:02 CEST 2013
The monad my code is currently written in is:
type MC = MCT Identity -- where MCT is the monad transformer version of it.
I have two options for threading state through this:
MCT (ST s) a
StateT s MC a
The first option would work if I had some function with the signature
MCT Identity a -> MCT (ST s) a
but I know of no such function, and the second one would work if I had some
way of making StateT a member of PrimMonad.
Can I see an example with 'lift'?
On Tuesday, April 16, 2013, Ivan Lazar Miljenovic wrote:
> > Hi list!
> > I want to use MVectors in a StateT monad transformer.
> > How do I do that? StateT isn't a member of 'PrimMonad', and I have no
> > how to make it one.
> You can use Control.Monad.Trans.lift to lift the PrimMonad operations
> to PrimMonad m => StateT s m
> > Regards,
> > - Clark
> > _______________________________________________
> > Haskell-Cafe mailing list
> > http://www.haskell.org/mailman/listinfo/haskell-cafe
> Ivan Lazar Miljenovic
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