On 3 July 2012 18:40, Vinzent <ru.vinz...@gmail.com> wrote: > Well, as far as I understand, protocols was made as they were on purpose, so > inability to create hierarchies is a "feature" (like it or not), while the > lack of `get-method`-like thing is clearly a defect (in my mind).
You can get hold of a protocol's implementation for a particular type if it was attached to a type with extend / extend-type / extend-protocol: (defprotocol IFoo (foo [x])) (deftype Foo [x] IFoo (foo [_] x)) (deftype Bar [x]) (extend-protocol IFoo Bar (foo [x] (.-x ^Bar x))) user=> (get-in IFoo [:impls user.Foo :foo]) nil user=> (get-in IFoo [:impls user.Bar :foo]) #<user$eval39$fn__40 user$eval39$fn__40@30c06258> :foo here is the keywordized method name. Implementations specified inline in a deftype/defrecord form cannot be so obtained, because they only exist as JVM methods. Basically by inlining an implementation you gain speed at the cost of some dynamic / reflective capabilities. You can also build implementation maps in a dynamic fashion when using extend (a regular function, unlike extend-protocol and extend-type which are macros); I believe there are some examples floating around in the group archives. Inlined implementation sharing requires some macrology, see for example the implementation of records. Cheers, Michał > > Anyway, you have multimethods which can do almost anything, so I think it'd > be a good idea to implement proof-of-concept of what you have in mind and > publish it on Github, so people could try it and compare to what they > already have. > > вторник, 3 июля 2012 г., 21:13:27 UTC+6 пользователь Warren Lynn написал: >> >> >> >> On Tuesday, July 3, 2012 4:18:44 AM UTC-4, Vinzent wrote: >>> >>> I believe the protocol's analogue for get-method would be enough. >>> >>> >> >> If here you mean we just need to use get-method to directly reuse a >> protocol method anywhere, I think that is not adequate. We need to maintain >> the hierarchy structure so even at run time we can re-define parent protocol >> methods and things will still work as expected for the derived type. >> Although, I also feel the free-style re-use of any method from anywhere >> (instead of always bundle all methods in one protocol together and following >> a hierarchy) may create some chaotic code structure that is difficult to >> understand, maintain and communicate with other developers. >> >> But get-method can be a building block here of course, and may be handy >> for those cases you do need ad-hoc re-use of some code. > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
