By the way I’m just wondering: Is there any reason why you can’t just use match-patterns instead of using ($ match-pattern) ?
And is there anything like a “generic-binding-expander” that would act sort of like a match-expander? And is there some kind of "generic-bind/renamed” module or something that provides everything from generic-bind except without the ~ in front? On Jul 15, 2014, at 3:02 PM, Stephen Chang <stch...@ccs.neu.edu> wrote: >> I just found this, which has a lot of forms for just about everything I can >> think of (and more) that support things like match-patterns: >> https://github.com/stchang/generic-bind >> >> I haven’t tried it yet, but It looks pretty amazing. >> >> It probably has everything you want. > > Thanks for the kind words. :) > > This was an experiment that tried to address a few questions that > repeatedly get asked on the mailing list: > > 1) that you can't destructure data structures at the binding site, and > 2) that you need to manually define many different versions of each > binding construct (eg define, match-define, match-define-values, etc), > which inevitably means that some binding forms don't exist (eg > match-for/X forms) > > Something like the expressivity problem for binding forms. > > I tried to implement one "generic" version of each binding form that > would accept many different "binding instances", so every binding form > would be extensible by implementing the appropriate instance (eg, a > matching instance, a values instance) > > Every Racket binding form should have a ~-prefixed version in my > library and my version should work as a drop-in replacement for its > Racket counterpart if you want to try it out. > > Here's a link to the docs if you're interested in reading more: > http://stchang.github.io/generic-bind/generic-bind.html > > (You can tell that it hasn't been updated in a while from the old css.) > > Caveat: my macro-fu hasn't quite reached expert level so I'd love for > anyone to tell me where my code is bad. > > That being said, I ran a large part of the Racket test suite using my > binding forms instead of the Racket ones so they should be usable in > most scenarios. > > > > > > > >> >> On Jul 13, 2014, at 12:41 AM, Alexander D. Knauth <alexan...@knauth.org> >> wrote: >> >>> >>> On Jul 12, 2014, at 10:17 PM, Alexander D. Knauth <alexan...@knauth.org> >>> wrote: >>> >>>> >>>> On Jul 12, 2014, at 6:43 PM, Brian Adkins <racketus...@lojic.com> wrote: >>>> >>>>> I probably won't keep my defpat macro, at least not in its present form >>>>> (for one, it only handles a single arg); there's probably a balance >>>>> between being concise and being general/flexible. >>>> >>>> Although define/match is definitely more powerful, if you want it, this >>>> would probably be a good version of what you want that would handle >>>> multiple arguments: (I’ll reply again if I get one to work with optional >>>> and/or keyword-arguments) >>>> (define-syntax defpat >>>> (syntax-rules () >>>> [(defpat (f arg-pat ...) body ...) >>>> (defpat f (match-lambda** [(arg-pat ...) body ...]))] >>>> [(defpat id expr) >>>> (define id expr)])) >>> >>> Ok I just made a version of defpat that can handle multiple arguments, >>> optional arguments, keyword-arguments, and optional keyword-arguments. >>> I also made a form called my-match-lambda that defpat uses to do this. >>> https://github.com/AlexKnauth/defpat >>> Also to do this I had to make it so that you have to use square brackets to >>> specify optional arguments, otherwise it couldn’t tell between an optional >>> argument and a match pattern. >>> >> >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
