.. efun:: closure symbol_variable(string arg)
  closure symbol_variable(symbol arg)
  closure symbol_variable(int arg)

  Constructs an identifier (lfun) closure from the global variable :arg:`arg` of the current program. The variable may be given as a symbol, by name, or by its ordinal number in the object's variable table.

  If there is no such variable, or if it is not visible outside the object, 0 is returned.

  If the argument is an integer, and the variable is both inherited and private in the inherited object (i.e. hidden), then a privilege violation will occur.

  .. usage::

    ::

      int base;
      int var;
      symbol_variable("var") // #'<this_object>->var
      symbol_variable(0)     // #'<this_object>->base

  :history 3.2.1@8 introduced:

  .. seealso:: :efun:`lambda`, :efun:`quote`, :efun:`symbol_function`