Question

I know that the library https://github.com/clojure/algo.generic provides ways of implementing generic arithmetic operators + * / - but there I couldn’t find a simple example of how to create them and then how to use it as a library.

say if I wanted to implement vector addition, etc:

> (+ [1 2 3 4 5] 5) 
;; => [6 7 8 9 10]

how would I go about:

• defining the + operator with algo.generic
• using the + operator previously defined within another project?

Answer 1

(ns your.custom.operators
  (:import
    clojure.lang.IPersistentVector)
  (:require
    [clojure.algo.generic.arithmetic :as generic]))

(defmethod generic/+
  [IPersistentVector Long]
  [v x]
  (mapv + v (repeat x)))

(ns your.consumer.project
  (:refer-clojure :exclude (+))
  (:use
    [clojure.algo.generic.arithmetic :only (+)])
  (:require
    your.custom.operators))

(defn add-five
  [v]
  (+ v 5))