On Sat, Oct 8, 2011 at 11:17 AM, Matthias Felleisen <matth...@ccs.neu.edu> wrote: > > On Oct 5, 2011, at 10:48 PM, Jay McCarthy wrote: > >> Okay. I think it is strange, but feel free to do that and revert my >> change. Apologies for the confusion.
> I think you shouldn't apologize here. I am unhappy that match > doesn't guarantee order of matching in a list. > > Sam should change the implementation not the documentation. I'm hoping to eventually use match for redex in order to get some performance improvement and I fear that disabling these optimizations would be bad news for me there. So I hope that's not what happens here. I don't mind if the ordering of calling the predicates is fixed when match cannot prove that the predicates are all safe to be reordered (presumably by match keeping a list of known-to-be-safe predicates somewhere and perhaps looking at the compile-time info to find struct predicates). (That would seem to be a straight-forward change, unless I'm missing something.) > The entire reason > I use lists is that I want left-to-right traversals. If I don't > I use 'no order' patterns. I don't think the above makes sense. Presumably you use lists when you want to *match* from left to right and no order when you don't care about the order of *matching the elements in the list*. But that's not really relevant for this discussion. Robby _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
