1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
;; Support code for generic interfaces
;; by Konrad Hinsen
;; last updated May 4, 2009
;; Copyright (c) Konrad Hinsen, 2009. All rights reserved. The use
;; and distribution terms for this software are covered by the Eclipse
;; Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
;; which can be found in the file epl-v10.html at the root of this
;; distribution. By using this software in any fashion, you are
;; agreeing to be bound by the terms of this license. You must not
;; remove this notice, or any other, from this software.
(ns
#^{:author "Konrad Hinsen"
:skip-wiki true
:doc "Generic interfaces
This library provides generic interfaces in the form of
multimethods that can be implemented for any type.
The interfaces partly duplicate existing non-generic
functions in clojure.core (arithmetic, comparison,
collections) and partly provide additional functions that
can be defined for a wide variety of types (functors, math
functions). More functions will be added in the future."}
clojure.contrib.generic
(:use [clojure.contrib.types :only (defadt)]))
;
; A dispatch function that separates nulary, unary, binary, and
; higher arity calls and also selects on type for unary and binary
; calls.
;
(defn nary-dispatch
([] ::nulary)
([x] (type x))
([x y]
[(type x) (type y)])
([x y & more] ::nary))
;
; We can't use [::binary :default], so we need to define a root type
; of the type hierarcy. The derivation for Object covers all classes,
; but all non-class types will need an explicit derive clause.
; Ultimately, a macro might take care of this.
;
(def root-type ::any)
(derive Object root-type)
;
; Symbols referring to ::nulary and ::n-ary
;
(def nulary-type ::nulary)
(def nary-type ::nary)
|
