testExpression (ExpressionParserTest)

    # File test/src/expression_test.rb, line 95
      def testExpression
        @use_around = false
        ops = OperatorTable.new do |tbl|
          tbl.infixl(plus, 20)
          tbl.infixl(minus, 20)
          tbl.infixl(mul, 40)
          tbl.infixl(space_mul, 40)
          tbl.infixl(div, 40)
          tbl.prefix(negate, 60)
          tbl.prefix(positive, 60)
          tbl.postfix(increment, 50)
          tbl.postfix(decrement, 50)
          tbl.infixr(rdiv, 40)
        end
        expr = nil
        term = int | char(?() >> lazy{expr} << char(?))
        delim = whitespace.many_
        expr = delim >> Expressions.build(term, ops, delim)

        assertParser('1', 1, expr)
        assertParser('1+2', 3, expr)
        assertParser('(1-2)', -1, expr)
        assertParser('2-3* 2', -4, expr)
        assertParser("\n ((2-3 )*-+2--) ", 3, expr)
        assertParser('((2-3 )*-+2--/2//2) ', 3, expr)
        assertParser('((2-3 )*-+2--/2//2--) ', 1, expr)
        assertParser('((2-3 )*-+2--//4//2) ', 2, expr)
        assertParser('((2-3 )*-+2--/2/2) ', 0, expr)
      end