alternations.js (1386B)
1 // Copyright (C) 2017 the V8 project authors. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 esid: sec-assertion 6 description: Alternations are tried left to right, and we do not backtrack into a lookbehind. 7 info: | 8 The production Assertion :: (?<=Disjunction) evaluates as follows: 9 1. Evaluate Disjunction with -1 as its direction argument to obtain a Matcher m. 10 2. Return an internal Matcher closure that takes two arguments, a State x and a Continuation 11 c, and performs the following steps: 12 a. Let d be a Continuation that always returns its State argument as a successful MatchResult. 13 b. Call m(x, d) and let r be its result. 14 c. If r is failure, return failure. 15 d. Let y be r's State. 16 e. Let cap be y's captures List. 17 f. Let xe be x's endIndex. 18 g. Let z be the State (xe, cap). 19 h. Call c(z) and return its result. 20 features: [regexp-lookbehind] 21 includes: [compareArray.js] 22 ---*/ 23 24 assert.compareArray("xabcd".match(/.*(?<=(..|...|....))(.*)/), ["xabcd", "cd", ""], "#1"); 25 assert.compareArray("xabcd".match(/.*(?<=(xx|...|....))(.*)/), ["xabcd", "bcd", ""], "#2"); 26 assert.compareArray("xxabcd".match(/.*(?<=(xx|...))(.*)/), ["xxabcd", "bcd", ""], "#3"); 27 assert.compareArray("xxabcd".match(/.*(?<=(xx|xxx))(.*)/), ["xxabcd", "xx", "abcd"], "#4"); 28 29 reportCompare(0, 0);