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// Copyright 2009 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Tests captures in positive and negative look-ahead in regular expressions.
function stringEscape(string) {
// Converts string to source literal.
return '"' + string.replace(/["\\]/g, "\\$1") + '"';
}
function testRE(re, input, expected_result) {
var testName = re + ".test(" + stringEscape(input) +")";
if (expected_result) {
assertTrue(re.test(input), testName);
} else {
assertFalse(re.test(input), testName);
}
}
function execRE(re, input, expected_result) {
var testName = re + ".exec('" + stringEscape(input) +"')";
assertEquals(expected_result, re.exec(input), testName);
}
// Test of simple positive lookahead.
var re = /^(?=a)/;
testRE(re, "a", true);
testRE(re, "b", false);
execRE(re, "a", [""]);
re = /^(?=\woo)f\w/;
testRE(re, "foo", true);
testRE(re, "boo", false);
testRE(re, "fao", false);
testRE(re, "foa", false);
execRE(re, "foo", ["fo"]);
re = /(?=\w).(?=\W)/;
testRE(re, ".a! ", true);
testRE(re, ".! ", false);
testRE(re, ".ab! ", true);
execRE(re, ".ab! ", ["b"]);
re = /(?=f(?=[^f]o))../;
testRE(re, ", foo!", true);
testRE(re, ", fo!", false);
testRE(re, ", ffo", false);
execRE(re, ", foo!", ["fo"]);
// Positive lookahead with captures.
re = /^[^\'\"]*(?=([\'\"])).*\1(\w+)\1/;
testRE(re, " 'foo' ", true);
testRE(re, ' "foo" ', true);
testRE(re, " \" 'foo' ", false);
testRE(re, " ' \"foo\" ", false);
testRE(re, " 'foo\" ", false);
testRE(re, " \"foo' ", false);
execRE(re, " 'foo' ", [" 'foo'", "'", "foo"]);
execRE(re, ' "foo" ', [' "foo"', '"', 'foo']);
// Captures are cleared on backtrack past the look-ahead.
re = /^(?:(?=(.))a|b)\1$/;
testRE(re, "aa", true);
testRE(re, "b", true);
testRE(re, "bb", false);
testRE(re, "a", false);
execRE(re, "aa", ["aa", "a"]);
execRE(re, "b", ["b", undefined]);
re = /^(?=(.)(?=(.)\1\2)\2\1)\1\2/;
testRE(re, "abab", true);
testRE(re, "ababxxxxxxxx", true);
testRE(re, "aba", false);
execRE(re, "abab", ["ab", "a", "b"]);
re = /^(?:(?=(.))a|b|c)$/;
testRE(re, "a", true);
testRE(re, "b", true);
testRE(re, "c", true);
testRE(re, "d", false);
execRE(re, "a", ["a", "a"]);
execRE(re, "b", ["b", undefined]);
execRE(re, "c", ["c", undefined]);
execRE(/^(?=(b))b/, "b", ["b", "b"]);
execRE(/^(?:(?=(b))|a)b/, "ab", ["ab", undefined]);
execRE(/^(?:(?=(b)(?:(?=(c))|d))|)bd/, "bd", ["bd", "b", undefined]);
// Test of Negative Look-Ahead.
re = /(?!x)./;
testRE(re, "y", true);
testRE(re, "x", false);
execRE(re, "y", ["y"]);
re = /(?!(\d))|\d/;
testRE(re, "4", true);
execRE(re, "4", ["4", undefined]);
execRE(re, "x", ["", undefined]);
// Test mixed nested look-ahead with captures.
re = /^(?=(x)(?=(y)))/;
testRE(re, "xy", true);
testRE(re, "xz", false);
execRE(re, "xy", ["", "x", "y"]);
re = /^(?!(x)(?!(y)))/;
testRE(re, "xy", true);
testRE(re, "xz", false);
execRE(re, "xy", ["", undefined, undefined]);
re = /^(?=(x)(?!(y)))/;
testRE(re, "xz", true);
testRE(re, "xy", false)
execRE(re, "xz", ["", "x", undefined]);
re = /^(?!(x)(?=(y)))/;
testRE(re, "xz", true);
testRE(re, "xy", false);
execRE(re, "xz", ["", undefined, undefined]);
re = /^(?=(x)(?!(y)(?=(z))))/;
testRE(re, "xaz", true);
testRE(re, "xya", true);
testRE(re, "xyz", false);
testRE(re, "a", false);
execRE(re, "xaz", ["", "x", undefined, undefined]);
execRE(re, "xya", ["", "x", undefined, undefined]);
re = /^(?!(x)(?=(y)(?!(z))))/;
testRE(re, "a", true);
testRE(re, "xa", true);
testRE(re, "xyz", true);
testRE(re, "xya", false);
execRE(re, "a", ["", undefined, undefined, undefined]);
execRE(re, "xa", ["", undefined, undefined, undefined]);
execRE(re, "xyz", ["", undefined, undefined, undefined]);