# File kwartz.rb, line 1967
        def translate_expr(node, code='', level=0)
            case tkn = node.token
            when :string
                value_str = node.left
                code << value_str.dump

        #    when :empty, :notempty
        #      ## s==empty  => (!s || s==''),  s!=empty => (s && s!='')
        #      flag = (tkn == :empty)
        #      str_node  = ExprNode.new(:string, '', nil)
        #      l_node    = flag ? ExprNode.new('!', node.left, nil) : node.left
        #      r_node    = ExprNode.new(flag ? '==' : '!=' , node.left, str_node)
        #      node2     = ExprNode.new(flag ? '||' : '&&', l_node, r_node)
        #      translate_expr(node2, code, level)

            else
                super(node, code, level)
            end
            return code
        end