SYNOPSIS
        closure symbol_variable(string arg)
        closure symbol_variable(symbol arg)
        closure symbol_variable(int arg)

DESCRIPTION
        Constructs an identifier (lfun) closure from the global
        variable arg of the current program. The variable may be given as a
        symbol, by name or by its ordinal number in the objects
        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 inherited
        and private in the inherited object (i.e. hidden), then a
        privilege violation will occur.

HISTORY
        Enabled since 3.2.1@8

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

SEE ALSO
        lambda(E), quote(E), symbol_function(E)