chickadee » scheme » <constant>

(quote <datum>)syntax

(quote <datum>) evaluates to <datum>. <Datum> may be any external representation of a Scheme object. 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>) may 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, and boolean constants evaluate "to themselves"; they need not be quoted.

'"abc"             ===>  "abc"
"abc"              ===>  "abc"
'145932            ===>  145932
145932             ===>  145932
'#t                ===>  #t
#t                 ===>  #t

It is an error to alter a constant (i.e. the value of a literal expression) using a mutation procedure like set-car! or string-set!. In the current implementation of CHICKEN, identical constants don't share memory and it is possible to mutate them, but this may change in the future.