On Nov 9, 2011, at 2:52 PM, Danny Yoo wrote: > I've been thinking about how to support hash-iterate-first and > hash-iterate-next in Whalesong. In Whalesong, my functional hash > implementation is based on left-leaning red-black trees. The > hash-iterate-* functions are a little weird for me since they return > numbers, and I had expected them to produce some opaque, structured > value. > > Since I can only use numbers, it makes iteration weirder since I'm > dealing with a non-linear structure. I cooked up a quick prototype of > an approach: > > http://www.wescheme.org/openEditor?publicId=shady-clunk-blase-saber-decay > > treating the number as binary digits, and using it as a description of > a path through the tree. > > Is this a reasonable approach?
This idea has a name in the FP community: director strings. It's the ultimate generalization of combinatorial programming (S distributes arguments, K distributes arguments in a different way, and director strings are general codes for distribution in a tree). -- Matthias _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
