// Copyright (c) 2016, 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.

// @dart = 2.9

/// @assertion Match matchAsPrefix(String string, [int start = 0])
/// Match this pattern against the start of string.
/// ...
/// Returns null if the pattern doesn't match.
/// @description Checks that null is returned when appropriate.
/// @author sgrekhov@unipro.ru

import "../../../Utils/expect.dart";
 
main() {
  check(r"\d+", "asfjkasfjkhasfj");
  check(r"^m", "pairs\nmakes\tdouble");
  check(r"s$", "pairs\nmakes\tdouble");
  check(r"^p[b-z]", "pairs\nmakes\tdouble\npesos");
  check(r"^..^e", "ab\ncde");
  check(r"\bot", "pilot\nsoviet robot\topenoffice");
}

void check(String pattern, String str) {
  RegExp re = new RegExp(pattern);
  Expect.equals(null, re.matchAsPrefix(str));
}