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11.7 Accessing Variable Values

The usual way to reference a variable is to write the symbol which names it (voir la section Symbol Forms). This requires you to specify the variable name when you write the program. Usually that is exactly what you want to do. Occasionally you need to choose at run time which variable to reference; then you can use symbol-value.

Function: symbol-value symbol

This function returns the value of symbol. This is the value in the innermost local binding of the symbol, or its global value if it has no local bindings.

 
(setq abracadabra 5)
     ⇒ 5
(setq foo 9)
     ⇒ 9

;; Here the symbol abracadabra
;;   is the symbol whose value is examined.
(let ((abracadabra 'foo))
  (symbol-value 'abracadabra))
     ⇒ foo

;; Here, the value of abracadabra,
;;   which is foo,
;;   is the symbol whose value is examined.
(let ((abracadabra 'foo))
  (symbol-value abracadabra))
     ⇒ 9

(symbol-value 'abracadabra)
     ⇒ 5

A void-variable error is signaled if the current binding of symbol is void.


Ce document a été généré par Eric Reinbold le 13 Octobre 2007 en utilisant texi2html 1.78.