48 lines
1.9 KiB
Clojure
48 lines
1.9 KiB
Clojure
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; "Lists can be expressed by function or a quoted form"
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(= '(1 2 3 4 5) (list 1 2 3 4 5))
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; "They are Clojure seqs (sequences), so they allow access to the first"
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(= 1 (first '(1 2 3 4 5)))
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; "As well as the rest"
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(= 2 3 4 5 (rest '(1 2 3 4 5))) ;; J -
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; "Count your blessings"
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(= 3 (count '(dracula dooku chocula)))
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; "Before they are gone"
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(= 0 (count '()))
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; "The rest, when nothing is left, is empty"
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(= (rest '(100))) ;; J - returns nothing.
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; "Construction by adding an element to the front is easy"
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(= :a :b :c :d :e (cons :a '(:b :c :d :e))) ;; J - cons add's the element on the left to the beginning
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;; of the list on the right and returns a seq.
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;;(EX: (cons [1 2] '(3 4 5)) => '([1 2] 3 4 5)
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; "Conjoining an element to a list isn't hard either"
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(= :a :b :c :d :e (conj '(:a :b :c :d) :e))
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;; J - conj works like cons, but takes any number of arguments from
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;; the right and adds them to the beginning of the list on the left
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;; returning them in the structure of whatever the list on the left is defined
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;; as originally. (EX: (conj [4 5 6] 1 2 3) => [1 2 3 4 5 6]
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; "You can use a list like a stack to get the first element"
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(= :a (peek '(:a :b :c :d :e))) ;; J - returns the first element
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; "Or the others"
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(= (:b) (pop '(:a :b :c :d :e))) ;; J - pops the first element and returns the others as a seq
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; "But watch out if you try to pop nothing"
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(= (try ;; J - Catch raises an error similar to 'raise' in Ruby.
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(pop '())
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(catch IllegalStateException e
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"No dice!")))
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; "The rest of nothing isn't so strict"
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(= () (try
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(rest '())
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(catch IllegalStateException e
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"No dice!")))
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