symbol-value

symbol-value Accessor

Syntax:

symbol-value symbol → value

(setf (symbol-value symbol) new-value**)**

Arguments and Values:

symbol—a symbol that must have a value.

value, new-value—an object.

Description:

Accesses the symbol’s value cell.

Examples:

(setf (symbol-value ’a) 1) → 1 
(symbol-value ’a) → 1 
;; SYMBOL-VALUE cannot see lexical variables. 
(let ((a 2)) (symbol-value ’a)) → 1 
(let ((a 2)) (setq a 3) (symbol-value ’a)) → 1 
;; SYMBOL-VALUE can see dynamic variables. 
(let ((a 2)) 
  (declare (special a)) 
  (symbol-value ’a)) → 2 
(let ((a 2)) 
  (declare (special a)) 
  (setq a 3) 
  (symbol-value ’a)) → 3 
(let ((a 2)) 
  (setf (symbol-value ’a) 3) 
  a) → 2 
a → 3 
(symbol-value ’a) → 3 
(let ((a 4)) 
  (declare (special a)) 
  (let ((b (symbol-value ’a))) 
    (setf (symbol-value ’a) 5) 
    (values a b))) → 5, 4 
a → 3 
(symbol-value :any-keyword) → :ANY-KEYWORD 
(symbol-value ’nil) → NIL 
(symbol-value ’()) → NIL 

;; The precision of this next one is *implementation-dependent*. 
(symbol-value ’pi) → 3.141592653589793d0 

Affected By:

makunbound, set, setq

Exceptional Situations:

Should signal an error of type type-error if symbol is not a symbol.

Should signal unbound-variable if symbol is unbound and an attempt is made to read its value. (No such error is signaled on an attempt to write its value.)

See Also:

boundp, makunbound, set, setq

Notes:

symbol-value can be used to get the value of a constant variable. symbol-value cannot access the value of a lexical variable.

Expanded Reference: symbol-value

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(symbol-value )