You cannot break out of a monad if all you have available to use are the monad typeclass functions, however there is nothing preventing an instance from being created that allows escape. Many of these escape methods come in the form of runX functions, but you can use constructors to break out with pattern matching if they are exposed.
As far as I can tell, IO is more of an outlier in this regard. (Did I miss something?) On Fri, Jul 30, 2010 at 2:23 PM, C K Kashyap <ckkash...@gmail.com> wrote: > Hi, > In the code here - > http://hpaste.org/fastcgi/hpaste.fcgi/view?id=28393#a28393 > If I look at the type of modifiedImage, its simply ByteString - but isn't it > actually getting into and back out of the state monad? I am of the > understanding that once you into a monad, you cant get out of it? Is this > breaking the "monad" scheme? > -- > Regards, > Kashyap > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
