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