On Thursday 31 May 2007 00:10:27 Stefan O'Rear wrote:
You said that constructing a specification is the hardest part of implementing Mathematica, and you also say you managed to clone it. Can you reveal your specification, or did WR give you a NDA?
NDA, although I did most of the reverse engineering independently beforehand. They use lots of nifty tricks (basically any trick that you can do easily in C) but there were plenty of other tricks they didn't try because they are far from obvious in C. I found an interesting alternative was to keep a lazily evaluated set of the symbols found in each subexpression. This could be used to cull searches and avoid unnecessary rewriting but also had no significant performance overhead. -- Dr Jon D Harrop, Flying Frog Consultancy Ltd. OCaml for Scientists http://www.ffconsultancy.com/products/ocaml_for_scientists/?e