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
Side Effects: None.
Affected By:
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.