On Wed, Dec 31, 2003 at 11:54:27AM +0000, Graham Klyne wrote: > My *intuition* here is that the problem is with countLeaves2, in that it > must build the computation for the given [sub]tree before it can start to > evaluate it. Maybe this is why other responses talk about changing the > state monad? > > But why does this computation have be done in a state monad at > all? countLeaves seems to me to be a pretty straightforward function from > a Tree to an Int, with no need for intervening state other than to > increment a counter: as such, I'd have expected a simple recursive > function to serve the purpose. (Maybe there was something in the original > application that was lost in the problem isolation?)
I think you might well be correct that I'm doing things the wrong way. The original program is a chess prog. and the function in question is the alphabeta search. I wanted to hold the transposition table (a cache of seen positions) among other things in the state monad. I thought this was the normal way to approach this, but am having doubts now. The recursive approach will indeed work, but I had hoped to avoid all the code associated with threading the state by hand. - Joe _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe