Literal expressions

(quote {datum} ) syntax
' {datum} syntax
{constant} syntax

(quote datum) evaluates to datum. Datum can be any external representation of a Scheme object (see section 3.3). This notation is used to include literal constants in Scheme code.
(quote a) =) a (quote #(a b c)) =) #(a b c) (quote (+ 1 2)) =) (+ 1 2)

(quote datum) can be abbreviated as 'datum. The two notations are equivalent in all respects.
'a ==> a '#(a b c) ==> #(a b c) '() ==> () '(+ 1 2) ==> (+ 1 2) '(quote a) ==> (quote a) ''a ==> (quote a)

Numerical constants, string constants, character constants, vector constants, bytevector constants, and boolean constants evaluate to themselves; they need not be quoted.
'145932 ==> 145932 145932 ==> 145932 '"abc" ==> "abc" "abc" ==> "abc" '#(a 10) ==> #(a 10) #(a 10) ==> #(a 10) '#u8(64 65) ==> #u8(64 65) #u8(64 65) ==> #u8(64 65) '#t ==> #t #t ==> #t

As noted in section 3.4, it is an error to attempt to alter a constant (i.e. the value of a literal expression) using a mutation procedure like set-car! or string-set!.

husk-scheme online documentation rev 3.19.3 (2016.07.10)