ST monad and monad tranformers

Josef Svenningsson josef.svenningsson at
Mon Feb 2 17:41:13 EST 2009

On Mon, Feb 2, 2009 at 8:50 PM, Reid Barton <rwbarton at> wrote:
> On Mon, Feb 02, 2009 at 06:03:15PM +0100, Josef Svenningsson wrote:
>> Hi Tyson,
>> I also needed something like this a while ago so I knocked up a really
>> simple module and put it on hackage:
> Warning!  The STMonadTrans package uses State# nonlinearly, and as a
> result, can violate referential transparency:
Indeed, thanks for pointing this out. I really should have a warning
sign on the package saying that it only works for certain monads.



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