LibTest/core/RegExp/Pattern_semantics/firstMatch_Term_A02_t01.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/**
 * @assertion 15.10.2.5: If the Atom and the sequel of the regular expression
 * all have choice points, the Atom is first matched as many (or as few, if
 * non-greedy) times as possible. All choices in the sequel are tried before
 * moving on to the next choice in the last repetition of Atom. All choices in
 * the last (Nth) repetition of Atom are tried before moving on to the next
 * choice in the next-to-last (N-1)st repetition of Atom; at which point it may
 * turn out that more or fewer repetitions of Atom are now possible; these are
 * exhausted (again, starting with either as few or as many as possible) before
 * moving on to the next choice in the (N-1)st repetition of Atom and so on.
 * @description Checks that matches are ordered according to this rule.
 * @3rdparty sputnik-v1:S15.10.2.5_A1_T3.js-S15.10.2.5_A1_T2.js
 * @author rodionov
 */
import "../../../../Utils/expect.dart";
 
main() {
  check("(aa|aabaac|ba|b|c)*", "aabaac", ["aaba", "ba"]);
  check(r"^(a+)\1*,\1+$", "aaaaaaaaa,aaaaaa", ["aaaaaaaaa,aaaaaa", "aaa"]);
  check(r"^(a+)\1*,\1+$", "aaaaaa,aaaaaaaaa", ["aaaaaa,aaaaaaaaa", "aaa"]);
  check(r"^(a+?)\1*,\1+$", "aaaaaaaaa,aaaaaa", ["aaaaaaaaa,aaaaaa", "a"]);
  check(r"^(a+?)\1*,\1+$", "aaaaaa,aaaaaaaaa", ["aaaaaa,aaaaaaaaa", "a"]);
}

void check(String pattern, String str, List<String> expectedGroups) {
  RegExp re = new RegExp(pattern);
  Expect.isNotNull(re.firstMatch(str));
  Match fm = re.firstMatch(str) as Match;
  if(null != expectedGroups) {
    Expect.equals(expectedGroups.length, fm.groupCount + 1);
    
    for(int i = 0; i <= fm.groupCount; i++) {
      String? expGr = expectedGroups[i];
      String? actGr = fm.group(i);
      Expect.equals(expGr, actGr,
          "Mismatch at group $i: \"$expGr\" expected instead of \"$actGr\"");
    }
  }
}