(defprotocol [psym & doc+methods])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
JavaScript parlance). defprotocol is dynamic, has no special compile-time
effect, and defines no new types.
(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
Examples
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