1 // Copyright 2015 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Flags: --harmony-regexp-lookbehind 6 7 // Simple fixed-length matches. 8 assertEquals(["a"], "a".match(/^.(?<=a)/)); 9 assertNull("b".match(/^.(?<=a)/)); 10 assertEquals(["foo"], "foo1".match(/^f..(?<=.oo)/)); 11 assertEquals(["foo"], "foo2".match(/^f\w\w(?<=\woo)/)); 12 assertNull("boo".match(/^f\w\w(?<=\woo)/)); 13 assertNull("fao".match(/^f\w\w(?<=\woo)/)); 14 assertNull("foa".match(/^f\w\w(?<=\woo)/)); 15 assertEquals(["def"], "abcdef".match(/(?<=abc)\w\w\w/)); 16 assertEquals(["def"], "abcdef".match(/(?<=a.c)\w\w\w/)); 17 assertEquals(["def"], "abcdef".match(/(?<=a\wc)\w\w\w/)); 18 assertEquals(["cde"], "abcdef".match(/(?<=a[a-z])\w\w\w/)); 19 assertEquals(["def"], "abcdef".match(/(?<=a[a-z][a-z])\w\w\w/)); 20 assertEquals(["def"], "abcdef".match(/(?<=a[a-z]{2})\w\w\w/)); 21 assertEquals(["bcd"], "abcdef".match(/(?<=a{1})\w\w\w/)); 22 assertEquals(["cde"], "abcdef".match(/(?<=a{1}b{1})\w\w\w/)); 23 assertEquals(["def"], "abcdef".match(/(?<=a{1}[a-z]{2})\w\w\w/)); 24 25 // Variable-length matches. 26 assertEquals(["def"], "abcdef".match(/(?<=[a|b|c]*)[^a|b|c]{3}/)); 27 assertEquals(["def"], "abcdef".match(/(?<=\w*)[^a|b|c]{3}/)); 28 29 // Start of line matches. 30 assertEquals(["def"], "abcdef".match(/(?<=^abc)def/)); 31 assertEquals(["def"], "abcdef".match(/(?<=^[a-c]{3})def/)); 32 assertEquals(["def"], "xyz\nabcdef".match(/(?<=^[a-c]{3})def/m)); 33 assertEquals(["ab", "cd", "efg"], "ab\ncd\nefg".match(/(?<=^)\w+/gm)); 34 assertEquals(["ab", "cd", "efg"], "ab\ncd\nefg".match(/\w+(?<=$)/gm)); 35 assertEquals(["ab", "cd", "efg"], "ab\ncd\nefg".match(/(?<=^)\w+(?<=$)/gm)); 36 assertNull("abcdef".match(/(?<=^[^a-c]{3})def/)); 37 assertNull("foooo".match(/"^foooo(?<=^o+)$/)); 38 assertNull("foooo".match(/"^foooo(?<=^o*)$/)); 39 assertEquals(["foo"], "foo".match(/^foo(?<=^fo+)$/)); 40 assertEquals(["foooo"], "foooo".match(/^foooo(?<=^fo*)/)); 41 assertEquals(["foo", "f"], "foo".match(/^(f)oo(?<=^\1o+)$/)); 42 assertEquals(["foo", "f"], "foo".match(/^(f)oo(?<=^\1o+)$/i)); 43 assertEquals(["foo\u1234", "f"], "foo\u1234".match(/^(f)oo(?<=^\1o+).$/i)); 44 assertEquals(["def"], "abcdefdef".match(/(?<=^\w+)def/)); 45 assertEquals(["def", "def"], "abcdefdef".match(/(?<=^\w+)def/g)); 46 47 // Word boundary matches. 48 assertEquals(["def"], "abc def".match(/(?<=\b)[d-f]{3}/)); 49 assertEquals(["def"], "ab cdef".match(/(?<=\B)\w{3}/)); 50 assertEquals(["def"], "ab cdef".match(/(?<=\B)(?<=c(?<=\w))\w{3}/)); 51 assertNull("abcdef".match(/(?<=\b)[d-f]{3}/)); 52 53 // Negative lookbehind. 54 assertEquals(["abc"], "abcdef".match(/(?<!abc)\w\w\w/)); 55 assertEquals(["abc"], "abcdef".match(/(?<!a.c)\w\w\w/)); 56 assertEquals(["abc"], "abcdef".match(/(?<!a\wc)\w\w\w/)); 57 assertEquals(["abc"], "abcdef".match(/(?<!a[a-z])\w\w\w/)); 58 assertEquals(["abc"], "abcdef".match(/(?<!a[a-z]{2})\w\w\w/)); 59 assertNull("abcdef".match(/(?<!abc)def/)); 60 assertNull("abcdef".match(/(?<!a.c)def/)); 61 assertNull("abcdef".match(/(?<!a\wc)def/)); 62 assertNull("abcdef".match(/(?<!a[a-z][a-z])def/)); 63 assertNull("abcdef".match(/(?<!a[a-z]{2})def/)); 64 assertNull("abcdef".match(/(?<!a{1}b{1})cde/)); 65 assertNull("abcdef".match(/(?<!a{1}[a-z]{2})def/)); 66 67 // Capturing matches. 68 assertEquals(["def", "c"], "abcdef".match(/(?<=(c))def/)); 69 assertEquals(["def", "bc"], "abcdef".match(/(?<=(\w{2}))def/)); 70 assertEquals(["def", "bc", "c"], "abcdef".match(/(?<=(\w(\w)))def/)); 71 assertEquals(["def", "a"], "abcdef".match(/(?<=(\w){3})def/)); 72 assertEquals(["d", "bc", undefined], "abcdef".match(/(?<=(bc)|(cd))./)); 73 assertEquals(["c", "a", undefined], 74 "abcdef".match(/(?<=([ab]{1,2})\D|(abc))\w/)); 75 assertEquals(["ab", "a", "b"], "abcdef".match(/\D(?<=([ab]+))(\w)/)); 76 assertEquals(["c", "d"], "abcdef".match(/(?<=b|c)\w/g)); 77 assertEquals(["cd", "ef"], "abcdef".match(/(?<=[b-e])\w{2}/g)); 78 79 // Captures inside negative lookbehind. (They never capture.) 80 assertEquals(["de", undefined], "abcdef".match(/(?<!(^|[ab]))\w{2}/)); 81 82 // Nested lookaround. 83 assertEquals(["ef"], "abcdef".match(/(?<=ab(?=c)\wd)\w\w/)); 84 assertEquals(["ef", "bc"], "abcdef".match(/(?<=a(?=([^a]{2})d)\w{3})\w\w/)); 85 assertEquals(["ef", "bc"], 86 "abcdef".match(/(?<=a(?=([bc]{2}(?<!a{2}))d)\w{3})\w\w/)); 87 assertNull("abcdef".match(/(?<=a(?=([bc]{2}(?<!a*))d)\w{3})\w\w/)); 88 assertEquals(["faaa"], "faaao".match(/^faaao?(?<=^f[oa]+(?=o))/)); 89 90 // Back references. 91 assertEquals(["b", "b", "bb"], "abb".match(/(.)(?<=(\1\1))/)); 92 assertEquals(["B", "B", "bB"], "abB".match(/(.)(?<=(\1\1))/i)); 93 assertEquals(["aB", "aB", "a"], "aabAaBa".match(/((\w)\w)(?<=\1\2\1)/i)); 94 assertEquals(["Ba", "Ba", "a"], "aabAaBa".match(/(\w(\w))(?<=\1\2\1)/i)); 95 assertEquals(["b", "b", "B"], "abaBbAa".match(/(?=(\w))(?<=(\1))./i)); 96 assertEquals(["foo", "'", "foo"], " 'foo' ".match(/(?<=(.))(\w+)(?=\1)/)); 97 assertEquals(["foo", "\"", "foo"], " \"foo\" ".match(/(?<=(.))(\w+)(?=\1)/)); 98 assertNull(" .foo\" ".match(/(?<=(.))(\w+)(?=\1)/)); 99 assertNull("ab".match(/(.)(?<=\1\1\1)/)); 100 assertNull("abb".match(/(.)(?<=\1\1\1)/)); 101 assertEquals(["b", "b"], "abbb".match(/(.)(?<=\1\1\1)/)); 102 assertNull("ab".match(/(..)(?<=\1\1\1)/)); 103 assertNull("abb".match(/(..)(?<=\1\1\1)/)); 104 assertNull("aabb".match(/(..)(?<=\1\1\1)/)); 105 assertNull("abab".match(/(..)(?<=\1\1\1)/)); 106 assertNull("fabxbab".match(/(..)(?<=\1\1\1)/)); 107 assertNull("faxabab".match(/(..)(?<=\1\1\1)/)); 108 assertEquals(["ab", "ab"], "fababab".match(/(..)(?<=\1\1\1)/)); 109 110 // Back references to captures inside the lookbehind. 111 assertEquals(["d", "C"], "abcCd".match(/(?<=\1(\w))d/i)); 112 assertEquals(["d", "x"], "abxxd".match(/(?<=\1([abx]))d/)); 113 assertEquals(["c", "ab"], "ababc".match(/(?<=\1(\w+))c/)); 114 assertEquals(["c", "b"], "ababbc".match(/(?<=\1(\w+))c/)); 115 assertNull("ababdc".match(/(?<=\1(\w+))c/)); 116 assertEquals(["c", "abab"], "ababc".match(/(?<=(\w+)\1)c/)); 117 118 // Alternations are tried left to right, 119 // and we do not backtrack into a lookbehind. 120 assertEquals(["xabcd", "cd", ""], "xabcd".match(/.*(?<=(..|...|....))(.*)/)); 121 assertEquals(["xabcd", "bcd", ""], "xabcd".match(/.*(?<=(xx|...|....))(.*)/)); 122 assertEquals(["xxabcd", "bcd", ""], "xxabcd".match(/.*(?<=(xx|...))(.*)/)); 123 assertEquals(["xxabcd", "xx", "abcd"], "xxabcd".match(/.*(?<=(xx|xxx))(.*)/)); 124 125 // We do not backtrack into a lookbehind. 126 // The lookbehind captures "abc" so that \1 does not match. We do not backtrack 127 // to capture only "bc" in the lookbehind. 128 assertNull("abcdbc".match(/(?<=([abc]+)).\1/)); 129 130 // Greedy loop. 131 assertEquals(["c", "bbbbbb"], "abbbbbbc".match(/(?<=(b+))c/)); 132 assertEquals(["c", "b1234"], "ab1234c".match(/(?<=(b\d+))c/)); 133 assertEquals(["c", "b12b23b34"], "ab12b23b34c".match(/(?<=((?:b\d{2})+))c/)); 134 135 // Sticky 136 var re1 = /(?<=^(\w+))def/g; 137 assertEquals(["def", "abc"], re1.exec("abcdefdef")); 138 assertEquals(["def", "abcdef"], re1.exec("abcdefdef")); 139 var re2 = /\Bdef/g; 140 assertEquals(["def"], re2.exec("abcdefdef")); 141 assertEquals(["def"], re2.exec("abcdefdef")); 142 143 // Misc 144 assertNull("abcdef".match(/(?<=$abc)def/)); 145 assertEquals(["foo"], "foo".match(/^foo(?<=foo)$/)); 146 assertEquals(["foo"], "foo".match(/^f.o(?<=foo)$/)); 147 assertNull("fno".match(/^f.o(?<=foo)$/)); 148 assertNull("foo".match(/^foo(?<!foo)$/)); 149 assertNull("foo".match(/^f.o(?<!foo)$/)); 150 assertEquals(["fno"], "fno".match(/^f.o(?<!foo)$/)); 151 assertEquals(["foooo"], "foooo".match(/^foooo(?<=fo+)$/)); 152 assertEquals(["foooo"], "foooo".match(/^foooo(?<=fo*)$/)); 153 assertEquals(["abc", "abc"], /(abc\1)/.exec("abc")); 154 assertEquals(["abc", "abc"], /(abc\1)/.exec("abc\u1234")); 155 assertEquals(["abc", "abc"], /(abc\1)/i.exec("abc")); 156 assertEquals(["abc", "abc"], /(abc\1)/i.exec("abc\u1234")); 157 var oob_subject = "abcdefghijklmnabcdefghijklmn".substr(14); 158 assertNull(oob_subject.match(/(?=(abcdefghijklmn))(?<=\1)a/i)); 159 assertNull(oob_subject.match(/(?=(abcdefghijklmn))(?<=\1)a/)); 160 161 // Mutual recursive capture/back references 162 assertEquals(["cacb", "a", ""], /(?<=a(.\2)b(\1)).{4}/.exec("aabcacbc")); 163 assertEquals(["b", "ac", "ac"], /(?<=a(\2)b(..\1))b/.exec("aacbacb")); 164 assertEquals(["x", "aa"], /(?<=(?:\1b)(aa))./.exec("aabaax")); 165 assertEquals(["x", "aa"], /(?<=(?:\1|b)(aa))./.exec("aaaax")); 166
