(quote ⟨datum⟩)‘(quote ⟨datum⟩)’ evaluates to ⟨datum⟩. ⟨Datum⟩ can be any external representation of a Scheme object (see External representations). 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 ⇒ #\a #\a ⇒ #\a '#(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 (Storage model), 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!.