clojure-koans/src/koans/lists.clj
2010-07-12 18:11:15 -05:00

35 lines
941 B
Clojure

(meditations
"Lists can be expressed by function or a quoted form"
(= '(__) (list 1 2 3 4 5))
"They are Clojure seqs (sequences), so they allow access to the first"
(= __ (first '(1 2 3 4 5)))
"As well as the rest"
(= __ (rest '(1 2 3 4 5)))
"The rest when nothing is left is empty"
(= __ (rest '(100)))
"And construction by adding an element to the front is simple"
(= __ (cons :a '(:b :c :d :e)))
"Conjoining an element to a list can be done in the reverse order"
(= __ (conj '(:a :b :c :d :e) 0))
"You can use a list like a stack to get the first element"
(= __ (peek '(:a :b :c :d :e)))
"Or the others"
(= __ (pop '(:a :b :c :d :e)))
"But watch out if you try to pop nothing"
(= __ (try
(pop '())
(catch IllegalStateException e "No dice!")))
"The rest of nothing isn't so strict"
(= __ (try
(rest '())
(catch IllegalStateException e "No dice!"))))