LibTest/core/RegExp/Pattern_semantics/firstMatch_Atom_A06_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 15.10.2.8: In case-insignificant matches all characters are
 * implicitly converted to upper case immediately before they are compared.
 * However, if converting a character to upper case would expand that character
 * into more than one character (such as converting "ß" (\u00DF) into "SS"),
 * then the character is left as-is instead. The character is also left as-is if
 * it is not an ASCII character but converting it to upper case would make it
 * into an ASCII character. This prevents Unicode characters such as \u0131 and
 * \u017F from matching regular expressions such as /[a-z]/i, which are only
 * intended to match ASCII letters. Furthermore, if these conversions were
 * allowed, then /[^\W]/i would match each of a, b, …, h, but not i or s.
 * @description Checks that this assertion is true.
 * @3rdparty sputnik-v1:S15.10.2.8_A5_T1.js-S15.10.2.8_A5_T2.js
 * @author rodionov
 */
import "../../../../Utils/expect.dart";
 

main() {
  check(r"[a-z]+", "ABC def ghi", ignoreCase: true, matchPos: 0,
      expectedGroups: ["ABC"]);
  check(r"[a-z]+", "ABC def ghi", matchPos: 4, expectedGroups: ["def"]);
  checkNeg(r"[A-Z]+", "ß", ignoreCase: true);
  checkNeg(r"[A-Z]+", "\u0131", ignoreCase: true);
  checkNeg(r"[A-Z]+", "\u017F", ignoreCase: true);
}

void check(String pattern, String str, {bool multiLine: false,
    bool ignoreCase: false, int matchPos: -1,
    List<String>? expectedGroups: null}) {
  RegExp re = new RegExp(pattern, multiLine: multiLine,
      caseSensitive: !ignoreCase);
  Expect.isNotNull(re.firstMatch(str), "\"$pattern\" !~ \"$str\"");
  Match fm = re.firstMatch(str) as Match;
  if(matchPos >= 0) {
    Expect.equals(matchPos, fm.start);
  }
  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\"");
    }
  }
}

void checkNeg(String pattern, String str, {bool multiLine: false,
    bool ignoreCase: false}) {
  RegExp re = new RegExp(pattern, multiLine: multiLine,
      caseSensitive: !ignoreCase);
  Expect.isNull(re.firstMatch(str), "\"$pattern\" ~ \"$str\"");
}