[Haskell-cafe] ANNOUNCE: pqueue-mtl, stateful-mtl

[Henning Thielemann]

On Sun, 15 Feb 2009, Louis Wasserman wrote:

> I follow.  The primary issue, I'm sort of wildly inferring, is that use of STT -- despite being
> pretty much a State monad on the inside -- allows access to things like mutable references?

I assume that ST must always be the most inner monad, like IO. Is this a 
problem in an application?