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Diffstat (limited to 'src/clojure/contrib/generic/arithmetic.clj')
| -rw-r--r-- | src/clojure/contrib/generic/arithmetic.clj | 201 |
1 files changed, 0 insertions, 201 deletions
diff --git a/src/clojure/contrib/generic/arithmetic.clj b/src/clojure/contrib/generic/arithmetic.clj deleted file mode 100644 index 90b6e659..00000000 --- a/src/clojure/contrib/generic/arithmetic.clj +++ /dev/null @@ -1,201 +0,0 @@ -;; Generic interfaces for arithmetic operations - -;; by Konrad Hinsen -;; last updated May 5, 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" - :doc "Generic arithmetic interface - This library defines generic versions of + - * / as multimethods - that can be defined for any type. The minimal required - implementations for a type are binary + and * plus unary - and /. - Everything else is derived from these automatically. Explicit - binary definitions for - and / can be provided for - efficiency reasons."} - clojure.contrib.generic.arithmetic - (:use [clojure.contrib.generic - :only (root-type nulary-type nary-type nary-dispatch)] - [clojure.contrib.types :only (defadt)]) - (:refer-clojure :exclude [+ - * /])) - -; -; Universal zero and one values -; -(defadt ::zero zero) -(defadt ::one one) - -(derive ::zero root-type) -(derive ::one root-type) - -; -; Addition -; -; The minimal implementation is for binary my-type. It is possible -; in principle to implement [::unary my-type] as well, though this -; doesn't make any sense. -; -(defmulti + - "Return the sum of all arguments. The minimal implementation for type - ::my-type is the binary form with dispatch value [::my-type ::my-type]." - {:arglists '([x] [x y] [x y & more])} - nary-dispatch) - -(defmethod + nulary-type - [] - zero) - -(defmethod + root-type - [x] x) - -(defmethod + [root-type ::zero] - [x y] x) - -(defmethod + [::zero root-type] - [x y] y) - -(defmethod + nary-type - [x y & more] - (if more - (recur (+ x y) (first more) (next more)) - (+ x y))) - -; -; Subtraction -; -; The minimal implementation is for unary my-type. A default binary -; implementation is provided as (+ x (- y)), but it is possible to -; implement unary my-type explicitly for efficiency reasons. -; -(defmulti - - "Return the difference of the first argument and the sum of all other - arguments. The minimal implementation for type ::my-type is the binary - form with dispatch value [::my-type ::my-type]." - {:arglists '([x] [x y] [x y & more])} - nary-dispatch) - -(defmethod - nulary-type - [] - (throw (java.lang.IllegalArgumentException. - "Wrong number of arguments passed"))) - -(defmethod - [root-type ::zero] - [x y] x) - -(defmethod - [::zero root-type] - [x y] (- y)) - -(defmethod - [root-type root-type] - [x y] (+ x (- y))) - -(defmethod - nary-type - [x y & more] - (if more - (recur (- x y) (first more) (next more)) - (- x y))) - -; -; Multiplication -; -; The minimal implementation is for binary [my-type my-type]. It is possible -; in principle to implement unary my-type as well, though this -; doesn't make any sense. -; -(defmulti * - "Return the product of all arguments. The minimal implementation for type - ::my-type is the binary form with dispatch value [::my-type ::my-type]." - {:arglists '([x] [x y] [x y & more])} - nary-dispatch) - -(defmethod * nulary-type - [] - one) - -(defmethod * root-type - [x] x) - -(defmethod * [root-type ::one] - [x y] x) - -(defmethod * [::one root-type] - [x y] y) - -(defmethod * nary-type - [x y & more] - (if more - (recur (* x y) (first more) (next more)) - (* x y))) - -; -; Division -; -; The minimal implementation is for unary my-type. A default binary -; implementation is provided as (* x (/ y)), but it is possible to -; implement binary [my-type my-type] explicitly for efficiency reasons. -; -(defmulti / - "Return the quotient of the first argument and the product of all other - arguments. The minimal implementation for type ::my-type is the binary - form with dispatch value [::my-type ::my-type]." - {:arglists '([x] [x y] [x y & more])} - nary-dispatch) - -(defmethod / nulary-type - [] - (throw (java.lang.IllegalArgumentException. - "Wrong number of arguments passed"))) - -(defmethod / [root-type ::one] - [x y] x) - -(defmethod / [::one root-type] - [x y] (/ y)) - -(defmethod / [root-type root-type] - [x y] (* x (/ y))) - -(defmethod / nary-type - [x y & more] - (if more - (recur (/ x y) (first more) (next more)) - (/ x y))) - -; -; Macros to permit access to the / multimethod via namespace qualification -; -(defmacro defmethod* - "Define a method implementation for the multimethod name in namespace ns. - Required for implementing the division function from another namespace." - [ns name & args] - (let [qsym (symbol (str ns) (str name))] - `(defmethod ~qsym ~@args))) - -(defmacro qsym - "Create the qualified symbol corresponding to sym in namespace ns. - Required to access the division function from another namespace, - e.g. as (qsym clojure.contrib.generic.arithmetic /)." - [ns sym] - (symbol (str ns) (str sym))) - -; -; Minimal implementations for java.lang.Number -; -(defmethod + [java.lang.Number java.lang.Number] - [x y] (clojure.core/+ x y)) - -(defmethod - java.lang.Number - [x] (clojure.core/- x)) - -(defmethod * [java.lang.Number java.lang.Number] - [x y] (clojure.core/* x y)) - -(defmethod / java.lang.Number - [x] (clojure.core// x)) - |