> 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
