test_peepholer.py 文件源码

def test_folding_of_binops_on_constants(self):
        for line, elem in (
            ('a = 2+3+4', 9),                   # chained fold
            ('"@"*4', '@@@@'),                  # check string ops
            ('a="abc" + "def"', 'abcdef'),      # check string ops
            ('a = 3**4', 81),                   # binary power
            ('a = 3*4', 12),                    # binary multiply
            ('a = 13//4', 3),                   # binary floor divide
            ('a = 14%4', 2),                    # binary modulo
            ('a = 2+3', 5),                     # binary add
            ('a = 13-4', 9),                    # binary subtract
            ('a = (12,13)[1]', 13),             # binary subscr
            ('a = 13 << 2', 52),                # binary lshift
            ('a = 13 >> 2', 3),                 # binary rshift
            ('a = 13 & 7', 5),                  # binary and
            ('a = 13 ^ 7', 10),                 # binary xor
            ('a = 13 | 7', 15),                 # binary or
            ):
            code = compile(line, '', 'single')
            self.assertInBytecode(code, 'LOAD_CONST', elem)
            for instr in dis.get_instructions(code):
                self.assertFalse(instr.opname.startswith('BINARY_'))

        # Verify that unfoldables are skipped
        code = compile('a=2+"b"', '', 'single')
        self.assertInBytecode(code, 'LOAD_CONST', 2)
        self.assertInBytecode(code, 'LOAD_CONST', 'b')

        # Verify that large sequences do not result from folding
        code = compile('a="x"*1000', '', 'single')
        self.assertInBytecode(code, 'LOAD_CONST', 1000)