Hey guys,
I'm having some issues with defining types using deftype and would
really appreciate some help.
Inspired by Mark Engelberg's PersistentPriorityMap
http://github.com/clojure/clojure-contrib/blob/master/modules/priority-map/src/main/clojure/clojure/contrib/priority_map.clj,
I decided to try out types and protocols with a MultiMap implementation
A MultiMap is just a map with more than one value associated with a key
and I created a new type (PersistentMultiMap) and a new Protocol
(MultiMap) with the following methods
(defprotocol MultiMap
(seq-pairs [this])
(assoc-swap [this key coll])
(conj-swap [this key-coll])
(dissoc-one [this key val]))
The problem is that the MultiMap protocol alone makes no semantic sense
without functions like assoc and dissoc, so updating MultiMap
(defprotocol MultiMap
(count [this])
(assoc [this key val])
(empty [this])
(cons [this e])
(equiv [this o])
(containsKey [this key])
(entryAt [this key])
(seq [this])
(without [this key])
(seq-pairs [this])
(conj-swap [this key-coll] [this key-coll & key-colls])
(assoc-swap [this key coll] [this key coll & key-colls])
(dissoc-one [this key val] [this key val & kvs]))
Great, now for the implementation.
My first attempt was a deftype (like the PersistentPriorityMap). The
problem was that since PersistentMultiMap also implemented
clojure.lang.IPersistentMap the methods clashed and the code would not
compile. #gist http://gist.github.com/580454#file_gistfile1.clj
After implementing MultiMap with extend-type, the code compiled and
everything worked fine #gist
http://gist.github.com/580454#file_gistfile2.clj
I removed the clashing methods and redefined it inline and then the
compilation went without a hitch #gist
http://gist.github.com/580454#file_gistfile3.clj
Is there any way to define the MultiMap protocol inline with the
clashing methods?
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