Hi Chris,
Thanks for the further pointers!
On Mon, Jul 28, 2008 at 11:12 AM, Chris Eidhof
Yes, indeed. However, folds are a nice way to factor out recursion and can make life a whole lot easier...In a way, folding is a really essential traversal of a data structure, so it can be seen as a primitive.
I'll admit to having seen folds before and being soundly impressed by how they capture a general pattern of recursion. Indeed, what actually prompted me to start this thread was that I had a function (updateTree) which did explicit recursion across a list, but I couldn't see a way to express it as (say) a fold. I guess I was wondering if there was any way to factor out the "updateTree" pattern of recursion in terms of simpler primitives (even though, for example, using a tree fold might be the more sensible choice for the particular example). -- Matt