Mercurial > lasercutter

     1 ;; Support code for generic interfaces

     2 

     3 ;; by Konrad Hinsen

     4 ;; last updated May 4, 2009

     5 

     6 ;; Copyright (c) Konrad Hinsen, 2009. All rights reserved.  The use

     7 ;; and distribution terms for this software are covered by the Eclipse

     8 ;; Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

     9 ;; which can be found in the file epl-v10.html at the root of this

    10 ;; distribution.  By using this software in any fashion, you are

    11 ;; agreeing to be bound by the terms of this license.  You must not

    12 ;; remove this notice, or any other, from this software.

    13 

    14 (ns

    15   ^{:author "Konrad Hinsen"

    16      :skip-wiki true

    17      :doc "Generic interfaces

    18            This library provides generic interfaces in the form of

    19            multimethods that can be implemented for any type.

    20            The interfaces partly duplicate existing non-generic

    21            functions in clojure.core (arithmetic, comparison,

    22            collections) and partly provide additional functions that

    23            can be defined for a wide variety of types (functors, math

    24            functions). More functions will be added in the future."}

    25   clojure.contrib.generic

    26   (:use [clojure.contrib.types :only (defadt)]))

    27 

    28 ;

    29 ; A dispatch function that separates nulary, unary, binary, and

    30 ; higher arity calls and also selects on type for unary and binary

    31 ; calls.

    32 ;

    33 (defn nary-dispatch

    34   ([] ::nulary)

    35   ([x] (type x))

    36   ([x y]

    37      [(type x) (type y)])

    38   ([x y & more] ::nary))

    39 

    40 ;

    41 ; We can't use [::binary :default], so we need to define a root type

    42 ; of the type hierarcy. The derivation for Object covers all classes,

    43 ; but all non-class types will need an explicit derive clause.

    44 ; Ultimately, a macro might take care of this.

    45 ;

    46 (def root-type ::any)

    47 (derive Object root-type)

    48 

    49 ;

    50 ; Symbols referring to ::nulary and ::n-ary

    51 ;

    52 (def nulary-type ::nulary)

    53 (def nary-type ::nary)

    54
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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