Info Catalog elisp: Tips for Defining elisp: Variables elisp: Setting Variables

elisp: Accessing Variables

 
 11.7 Accessing Variable Values
 ==============================
 
 The usual way to reference a variable is to write the symbol which names
 it.  Symbol Forms.
 
    Occasionally, you may want to reference a variable which is only
 determined at run time.  In that case, you cannot specify the variable
 name in the text of the program.  You can use the ‘symbol-value’
 function to extract the value.
 
  -- Function: symbol-value symbol
      This function returns the value stored in SYMBOL’s value cell.
      This is where the variable’s current (dynamic) value is stored.  If
      the variable has no local binding, this is simply its global value.
      If the variable is void, a ‘void-variable’ error is signaled.
 
      If the variable is lexically bound, the value reported by
      ‘symbol-value’ is not necessarily the same as the variable’s
      lexical value, which is determined by the lexical environment
      rather than the symbol’s value cell.  Variable Scoping.
 
           (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
 

Info Catalog elisp: Tips for Defining elisp: Variables elisp: Setting Variables