clojure-koans/src/koans/15_destructuring.clj

45 lines
1.3 KiB
Clojure

(ns koans.15-destructuring
(:require [koan-engine.core :refer :all]))
(def test-address
{:street-address "123 Test Lane"
:city "Testerville"
:state "TX"})
(meditations
"Destructuring is an arbiter: it breaks up arguments"
(= __ ((fn [[a b]] (str b a))
[:foo :bar]))
"Whether in function definitions"
(= (str "An Oxford comma list of apples, "
"oranges, "
"and pears.")
((fn [[a b c]] __)
["apples" "oranges" "pears"]))
"Or in let expressions"
(= "Rich Hickey aka The Clojurer aka Go Time aka Lambda Guru"
(let [[first-name last-name & aliases]
(list "Rich" "Hickey" "The Clojurer" "Go Time" "Lambda Guru")]
__))
"You can regain the full argument if you like arguing"
(= {:original-parts ["Stephen" "Hawking"] :named-parts {:first "Stephen" :last "Hawking"}}
(let [[first-name last-name :as full-name] ["Stephen" "Hawking"]]
__))
"Break up maps by key"
(= "123 Test Lane, Testerville, TX"
(let [{street-address :street-address, city :city, state :state} test-address]
__))
"Or more succinctly"
(= "123 Test Lane, Testerville, TX"
(let [{:keys [street-address __ __]} test-address]
__))
"All together now!"
(= "Test Testerson, 123 Test Lane, Testerville, TX"
(___ ["Test" "Testerson"] test-address)))