April 2012
Intermediate to advanced
296 pages
7h 3m
English
Content preview from Programming Clojure, 2nd Edition
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Creating Ad Hoc Taxonomies
Multimethods let you create ad hoc taxonomies, which can be helpful when you discover type relationships that are not explicitly declared as such.
For example, consider a financial application that deals with checking and savings accounts. Define a Clojure struct for an account, using a tag to distinguish the two. Place the code in the namespace examples.multimethods.account. To do this, you will need to create a file named examples/multimethods/account.clj on your classpath[57] and then enter the following code:
| src/examples/multimethods/account.clj | |
(ns examples.multimethods.account) | |
| |
(defstruct account :id :tag :balance) | |
Now, you are going to create two different checking accounts, tagged as ::Checking ...
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