Clojure Programming Cookbook

Defining multimethods

Defining multimethods is another way to realize polymorphism. The multimethod has a strong dispatch mechanism for polymorphism. Let's see how it works.

Getting ready

You need to add the math.numeric-tower to your project.clj file to run samples (or any other dependency management you are using):

:dependencies 
  [[org.clojure/clojure "1.8.0"] 
   [org.clojure/math.numeric-tower "0.0.4"] 
                 ] 

How to do it...

Let's see how to define and use multimethods.

Defining a multimethod

The defmulti creates new multimethods, and the defmethod creates and implements a new method of multimethod associated with a dispatch value.

The following code shows an example of the defmulti of the calculation of the volume of shapes. The first argument is the name ...