ST monad and monad tranformers

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


On Mon, Feb 2, 2009 at 8:50 PM, Reid Barton <rwbarton at math.harvard.edu> 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:
>> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/STMonadTrans
>
> 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.

Cheers,

/Josef


More information about the Glasgow-haskell-users mailing list