1 // Copyright 2009 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 // Tests captures in positive and negative look-ahead in regular expressions. 29 30 function stringEscape(string) { 31 // Converts string to source literal. 32 return '"' + string.replace(/["\\]/g, "\\$1") + '"'; 33 } 34 35 function testRE(re, input, expected_result) { 36 var testName = re + ".test(" + stringEscape(input) +")"; 37 if (expected_result) { 38 assertTrue(re.test(input), testName); 39 } else { 40 assertFalse(re.test(input), testName); 41 } 42 } 43 44 function execRE(re, input, expected_result) { 45 var testName = re + ".exec('" + stringEscape(input) +"')"; 46 assertEquals(expected_result, re.exec(input), testName); 47 } 48 49 // Test of simple positive lookahead. 50 51 var re = /^(?=a)/; 52 testRE(re, "a", true); 53 testRE(re, "b", false); 54 execRE(re, "a", [""]); 55 56 re = /^(?=\woo)f\w/; 57 testRE(re, "foo", true); 58 testRE(re, "boo", false); 59 testRE(re, "fao", false); 60 testRE(re, "foa", false); 61 execRE(re, "foo", ["fo"]); 62 63 re = /(?=\w).(?=\W)/; 64 testRE(re, ".a! ", true); 65 testRE(re, ".! ", false); 66 testRE(re, ".ab! ", true); 67 execRE(re, ".ab! ", ["b"]); 68 69 re = /(?=f(?=[^f]o))../; 70 testRE(re, ", foo!", true); 71 testRE(re, ", fo!", false); 72 testRE(re, ", ffo", false); 73 execRE(re, ", foo!", ["fo"]); 74 75 // Positive lookahead with captures. 76 re = /^[^\'\"]*(?=([\'\"])).*\1(\w+)\1/; 77 testRE(re, " 'foo' ", true); 78 testRE(re, ' "foo" ', true); 79 testRE(re, " \" 'foo' ", false); 80 testRE(re, " ' \"foo\" ", false); 81 testRE(re, " 'foo\" ", false); 82 testRE(re, " \"foo' ", false); 83 execRE(re, " 'foo' ", [" 'foo'", "'", "foo"]); 84 execRE(re, ' "foo" ', [' "foo"', '"', 'foo']); 85 86 // Captures are cleared on backtrack past the look-ahead. 87 re = /^(?:(?=(.))a|b)\1$/; 88 testRE(re, "aa", true); 89 testRE(re, "b", true); 90 testRE(re, "bb", false); 91 testRE(re, "a", false); 92 execRE(re, "aa", ["aa", "a"]); 93 execRE(re, "b", ["b", undefined]); 94 95 re = /^(?=(.)(?=(.)\1\2)\2\1)\1\2/; 96 testRE(re, "abab", true); 97 testRE(re, "ababxxxxxxxx", true); 98 testRE(re, "aba", false); 99 execRE(re, "abab", ["ab", "a", "b"]); 100 101 re = /^(?:(?=(.))a|b|c)$/; 102 testRE(re, "a", true); 103 testRE(re, "b", true); 104 testRE(re, "c", true); 105 testRE(re, "d", false); 106 execRE(re, "a", ["a", "a"]); 107 execRE(re, "b", ["b", undefined]); 108 execRE(re, "c", ["c", undefined]); 109 110 execRE(/^(?=(b))b/, "b", ["b", "b"]); 111 execRE(/^(?:(?=(b))|a)b/, "ab", ["ab", undefined]); 112 execRE(/^(?:(?=(b)(?:(?=(c))|d))|)bd/, "bd", ["bd", "b", undefined]); 113 114 115 116 // Test of Negative Look-Ahead. 117 118 re = /(?!x)./; 119 testRE(re, "y", true); 120 testRE(re, "x", false); 121 execRE(re, "y", ["y"]); 122 123 re = /(?!(\d))|\d/; 124 testRE(re, "4", true); 125 execRE(re, "4", ["4", undefined]); 126 execRE(re, "x", ["", undefined]); 127 128 129 // Test mixed nested look-ahead with captures. 130 131 re = /^(?=(x)(?=(y)))/; 132 testRE(re, "xy", true); 133 testRE(re, "xz", false); 134 execRE(re, "xy", ["", "x", "y"]); 135 136 re = /^(?!(x)(?!(y)))/; 137 testRE(re, "xy", true); 138 testRE(re, "xz", false); 139 execRE(re, "xy", ["", undefined, undefined]); 140 141 re = /^(?=(x)(?!(y)))/; 142 testRE(re, "xz", true); 143 testRE(re, "xy", false) 144 execRE(re, "xz", ["", "x", undefined]); 145 146 re = /^(?!(x)(?=(y)))/; 147 testRE(re, "xz", true); 148 testRE(re, "xy", false); 149 execRE(re, "xz", ["", undefined, undefined]); 150 151 re = /^(?=(x)(?!(y)(?=(z))))/; 152 testRE(re, "xaz", true); 153 testRE(re, "xya", true); 154 testRE(re, "xyz", false); 155 testRE(re, "a", false); 156 execRE(re, "xaz", ["", "x", undefined, undefined]); 157 execRE(re, "xya", ["", "x", undefined, undefined]); 158 159 re = /^(?!(x)(?=(y)(?!(z))))/; 160 testRE(re, "a", true); 161 testRE(re, "xa", true); 162 testRE(re, "xyz", true); 163 testRE(re, "xya", false); 164 execRE(re, "a", ["", undefined, undefined, undefined]); 165 execRE(re, "xa", ["", undefined, undefined, undefined]); 166 execRE(re, "xyz", ["", undefined, undefined, undefined]); 167
