nullable-quantifier.js (1226B)
1 // Copyright (C) 2024 Aurèle Barrière. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 esid: sec-runtime-semantics-repeatmatcher-abstract-operation 6 description: JavaScript nullable quantifiers have special semantics, optional iterations are not allowed to match the empty string. Point 2.b below shows that after each optional (min=0) iteration of a quantifier, if the iteration matched the empty string (y.[[EndIndex]] = x.[[EndIndex]]), then the iteration is discarded. In particular, for (a?b??)* on "ab", it is possible to do two iterations of the star, one matching "a" and the other matching "b". 7 info: | 8 RepeatMatcher ( m, min, max, greedy, x, c, parenIndex, parenCount ) 9 10 2. Let d be a new MatcherContinuation with parameters (y) that captures m, min, max, greedy, x, c, parenIndex, and parenCount and performs the following steps when called: 11 12 b. If min = 0 and y.[[EndIndex]] = x.[[EndIndex]], return failure. 13 author: Aurèle Barrière 14 ---*/ 15 16 let input = "ab"; 17 let regex = /(a?b??)*/; 18 let match = regex.exec(input); 19 let expected = "ab"; 20 21 assert.sameValue(match[0], expected, "The regex is expected to match the whole string"); 22 23 reportCompare(0, 0);