9 The quote form🔗ℹ

A quote form can also be written by putting a single-quote (apostrophe) before an expression. 'datum is equivalent to (quote datum).

Quoting a name creates a symbol. Quoting a piece of literal data like a number, boolean, or string produces that same number, boolean, or string.

> 'antithesis

'antithesis

> '42

42

> 'nil

nil

> '"literal literal"

"literal literal"

It gets more complicitated when you use it with parentheses. It creates a list, but it also "distributes itself" over everything within it, including to every element of the list. So (quote (datum ...)) is equivalent to (list (quote datum) ...).

> '(this is not a pipe)

(list 'this 'is 'not 'a 'pipe)

> '(this is not a five: (+ 2 3))

(list 'this 'is 'not 'a 'five: (list '+ 2 3))

> '(((distributes) ((((((((arbitrarily)))) far))))))

(list  (list   (list 'distributes)   (list (list (list (list (list (list (list (list 'arbitrarily)))) 'far))))))

> (defunc my-function (a)     :input-contract t     :output-contract t     42)

> '(functions are not evaluated: (my-function 5))

(list 'functions 'are 'not 'evaluated: (list 'my-function 5))

> '(not even quote is evaluated: '5)

(list 'not 'even 'quote 'is 'evaluated: (list 'quote 5))

; keep in mind '5 is another way of writing (quote 5)

> ''5

(list 'quote 5)

> '('5)

(list (list 'quote 5))