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Issues #814253, #9179: Group references and conditional group references now

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work in lookbehind assertions in regular expressions.
This commit is contained in:
Serhiy Storchaka 2015-02-21 10:07:35 +02:00
parent df80706f14
commit 4eea62fd2e
5 changed files with 92 additions and 12 deletions
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42
Lib/test/test_re.py
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@ -604,7 +604,7 @@ class ReTests(unittest.TestCase):
self.assertEqual(re.match("a.*b", "a\n\nb", re.DOTALL).group(0),
"a\n\nb")
def test_non_consuming(self):
def test_lookahead(self):
self.assertEqual(re.match("(a(?=\s[^a]))", "a b").group(1), "a")
self.assertEqual(re.match("(a(?=\s[^a]*))", "a b").group(1), "a")
self.assertEqual(re.match("(a(?=\s[abc]))", "a b").group(1), "a")
@ -618,6 +618,46 @@ class ReTests(unittest.TestCase):
self.assertEqual(re.match(r"(a)(?!\s\1)", "a b").group(1), "a")
self.assertEqual(re.match(r"(a)(?!\s(abc|a))", "a b").group(1), "a")
# Group reference.
self.assertTrue(re.match(r'(a)b(?=\1)a', 'aba'))
self.assertIsNone(re.match(r'(a)b(?=\1)c', 'abac'))
# Conditional group reference.
self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(2)x|c))c', 'abc'))
self.assertIsNone(re.match(r'(?:(a)|(x))b(?=(?(2)c|x))c', 'abc'))
self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(2)x|c))c', 'abc'))
self.assertIsNone(re.match(r'(?:(a)|(x))b(?=(?(1)b|x))c', 'abc'))
self.assertTrue(re.match(r'(?:(a)|(x))b(?=(?(1)c|x))c', 'abc'))
# Group used before defined.
self.assertTrue(re.match(r'(a)b(?=(?(2)x|c))(c)', 'abc'))
self.assertIsNone(re.match(r'(a)b(?=(?(2)b|x))(c)', 'abc'))
self.assertTrue(re.match(r'(a)b(?=(?(1)c|x))(c)', 'abc'))
def test_lookbehind(self):
self.assertTrue(re.match(r'ab(?<=b)c', 'abc'))
self.assertIsNone(re.match(r'ab(?<=c)c', 'abc'))
self.assertIsNone(re.match(r'ab(?<!b)c', 'abc'))
self.assertTrue(re.match(r'ab(?<!c)c', 'abc'))
# Group reference.
self.assertTrue(re.match(r'(a)a(?<=\1)c', 'aac'))
self.assertIsNone(re.match(r'(a)b(?<=\1)a', 'abaa'))
self.assertIsNone(re.match(r'(a)a(?<!\1)c', 'aac'))
self.assertTrue(re.match(r'(a)b(?<!\1)a', 'abaa'))
# Conditional group reference.
self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(2)x|c))c', 'abc'))
self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(2)b|x))c', 'abc'))
self.assertTrue(re.match(r'(?:(a)|(x))b(?<=(?(2)x|b))c', 'abc'))
self.assertIsNone(re.match(r'(?:(a)|(x))b(?<=(?(1)c|x))c', 'abc'))
self.assertTrue(re.match(r'(?:(a)|(x))b(?<=(?(1)b|x))c', 'abc'))
# Group used before defined.
self.assertRaises(re.error, re.compile, r'(a)b(?<=(?(2)b|x))(c)')
self.assertIsNone(re.match(r'(a)b(?<=(?(1)c|x))(c)', 'abc'))
self.assertTrue(re.match(r'(a)b(?<=(?(1)b|x))(c)', 'abc'))
# Group defined in the same lookbehind pattern
self.assertRaises(re.error, re.compile, r'(a)b(?<=(.)\2)(c)')
self.assertRaises(re.error, re.compile, r'(a)b(?<=(?P<a>.)(?P=a))(c)')
self.assertRaises(re.error, re.compile, r'(a)b(?<=(a)(?(2)b|x))(c)')
self.assertRaises(re.error, re.compile, r'(a)b(?<=(.)(?<=\2))(c)')
def test_ignore_case(self):
self.assertEqual(re.match("abc", "ABC", re.I).group(0), "ABC")
self.assertEqual(re.match(b"abc", b"ABC", re.I).group(0), b"ABC")