No. Mutable sets would implement gen:set and then just have a few more methods in the gen:mset interface. Structs can implement any number of generics.
Jay On Wed, Oct 2, 2013 at 1:31 PM, J. Ian Johnson <i...@ccs.neu.edu> wrote: > This means I can't interchange between mutable and immutable sets for my > functions that only need to read generic sets, unless we further subdivide > and have gen:set-query gen:set-constructor gen:set-mconstruct. > > -Ian > ----- Original Message ----- > From: "Jay McCarthy" <jay.mccar...@gmail.com> > To: "Carl Eastlund" <c...@ccs.neu.edu> > Cc: "Racket Developers" <dev@racket-lang.org> > Sent: Wednesday, October 2, 2013 3:23:07 PM GMT -05:00 US/Canada Eastern > Subject: Re: [racket-dev] Generics updates > > Regarding a point from RacketCon, I don't like that gen:set includes > functions like set-add! and set-remove!. I think that sets with > mutations are subclass of get:set and we should have a separate > gen:mset (or something) interface for mutable versions. > > I dislike that an obvious implementation of sets, hash tables, are not > sets to gen:set, because there are operations that cannot be performed > on them. > > I think that "X implements generic G" should imply "All functions of G > work on X". But this is not the case with gen:set and hasheq sets, for > instance. > > Jay > > > On Tue, Jul 23, 2013 at 9:37 AM, Carl Eastlund <c...@ccs.neu.edu> wrote: >> My work on adding gen:set, and related changes to define-generics and >> gen:dict, is ready for review and (hopefully) to push to the master branch. >> The branch moved in the process of cleaning things up, it's now at: >> >> https://github.com/carl-eastlund/racket/tree/generics-from-scratch >> >> (The "from scratch" just refers to the process of rebuilding the git >> history, I didn't go out of my way to rewrite anything in the code base from >> scratch, although in some places a lot of code did move around.) >> >> What's new in the branch: >> >> - Generics now support a few new options >> - #:fallbacks specifies fallback method implementations for instances with >> no implementation >> - #:fast-defaults specifies instances on a "fast path", useful for >> built-in types >> - #:defined-predicate gives a more intuitive and efficient interface than >> #:defined-table >> - #:derive-property allows generics to piggy-back on existing struct >> properties >> >> - Sets are now a generic datatype through gen:set >> - lists are now sets >> - the built-in set types are now documented as "hash sets" >> - there are mutable and weak hash sets >> - you can define new set types quickly with define-custom-set-types >> - most set operations are now methods with fallbacks >> - sets now support -copy and -clear operations, plus mutating [!] versions >> of operations >> >> - Dictionaries have a few changes >> - new macro define-custom-hash-types [*] >> - most dict operations are now methods with fallbacks >> - dicts now support -copy, -clear, -clear!, and -empty? operations >> >> I've run some benchmarks and performance of the various generic operations >> are comparable to the current HEAD, so there should be no major performance >> changes with this patch. >> >> [*] I've added define-custom-hash-types and define-custom-set-types rather >> than just adding make-custom-set akin to make-custom-hash because >> make-custom-hash is hard to use. The documented behavior -- that any custom >> hash is equal to any other created with the same bindings and predicates / >> hash functions -- was never true and can be expensive or at least tricky to >> implement. It seemed more sensible to just remove the erroneous >> documentation on make-custom-hash, and add the definition form to create >> constructors for new, explicitly-compatible dict and set types. Both >> definition forms bind predicates and constructors for new (set or dict) >> types with immutable, mutable, and weak variants that inter-operate. >> >> If there are no serious issues brought up in the next day or two, I'll push >> it to the development branch, since our current release process isn't >> following HEAD. >> >> Carl Eastlund >> >> _________________________ >> Racket Developers list: >> http://lists.racket-lang.org/dev >> > > > > -- > Jay McCarthy <j...@cs.byu.edu> > Assistant Professor / Brigham Young University > http://faculty.cs.byu.edu/~jay > > "The glory of God is Intelligence" - D&C 93 > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev -- Jay McCarthy <j...@cs.byu.edu> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93 _________________________ Racket Developers list: http://lists.racket-lang.org/dev