Thanks for the wonderful post earlier on memoization Stefan.

I'm still trying to wrap my head around all the details. For example I'm trying to figure out why (in the second version) the constant "is" scoped within the function isn't garbage collected in between different calls to the function. It seems like there is a lot going on behind the scenes, and even though things look "semantically correct" to a beginner, they aren't so straightforward. :) I think I will re-read your post a couple more time, and hopefully get some more insight.

BTW, Sorry I didn't notice your update earlier. For some reason, I only get certain emails from this list, and others disappear down a black hole. I just happened to browse the archives and noticed this response.

Is there a web interface or such to browse and/or respond to threads? I just usually mail "beginners@haskell.org" which is a painful way to do this... (unless I'm doing it wrong).