result.clj

<fliebel> (doc defprotocol)
<sexpbot> ⟹ "Macro ([name & opts+sigs]); A protocol is a named set of
named methods and their signatures: (defprotocol AProtocolName
;optional doc string \"A doc string for AProtocol abstraction\"
;method signatures (bar [this a b] \"bar docs\") (baz [this a] [this a
b] [this a b c] \"baz docs\")) No implementations are provided. Docs
can be specified for the protocol overall and for each method. The
above yields a set of polymorphic functions and a protocol object. All
are namespace-qualified by the ns enclosing the definition The
resulting functions dispatch on the type of their first argument,
which is required and corresponds to the implicit target object
('this' in Java parlance). defprotocol is dynamic, has no special
compile-time effect, and defines no new types or classes.
Implementations of the protocol methods can be provided using extend.
defprotocol will automatically generate a corresponding interface,
with the same name as the protocol, i.e. given a protocol:
my.ns/Protocol, an interface: my.ns.Protocol. The interface will have
methods corresponding to the protocol functions, and the protocol will
automatically work with instances of the interface. Note that you
should not use this interface with deftype or reify, as they support
the protocol directly: (defprotocol P (foo [this]) (bar-me [this]
[this y])) (deftype Foo [a b c] P (foo [this] a) (bar-me [this] b)
(bar-me [this y] (+ c y))) (bar-me (Foo. 1 2 3) 42) => 45 (foo (let [x
42] (reify P (foo [this] 17) (bar-me [this] x) (bar-me [this y] x))))
=> 17"