Re: [Haskell-cafe] A tale of Project Euler

On Thu, Nov 29, 2007 at 09:10:16PM +0000, Andrew Coppin wrote:

Sebastian Sylvan wrote:

...

On Nov 29, 2007 6:43 PM, Andrew Coppin wrote:

...

I don't understand the ST monad.

There's not a whole lot to understand if you just want to use it (though it's all very cool from a theoretical standpoint too).

From what I can tell, it's not definable without using strange language extensions. (I don't really like using things where it's unclear why it works.)

You can't implement IO in H98 either. You just have to accept it as a given. (As far as ST goes, runST is unsafePerformIO renamed. The only tricky bit is proving safety.) Stefan