LanguageFeatures/Spread-collections/Syntax_A01_t03.dart

// Copyright (c) 2019, 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 We extend the list grammar to allow spread elements in addition to
/// regular elements:
/// listLiteral:
///   const? typeArguments? '[' spreadableList? ']'
///   ;
///
///   spreadableList:
///   spreadableExpression ( ',' spreadableExpression )* ','?
///   ;
///
///   spreadableExpression:
///   expression |
///   spread
///   ;
///
///   spread:
///   ( '...' | '...?' ) expression
///   ;
///
/// Instead of [expressionList], this uses a new [spreadableList] rule since
/// [expressionList] is used elsewhere in the grammar where spreads aren't
/// allowed. Each element in a list is either a normal expression or a spread
/// element. If the spread element starts with [...?], it's a null-aware spread
/// element.
/// @description Checks that [spreadableList] can be constant
/// @author iarkh@unipro.ru


import "../../Utils/expect.dart";

main() {
  const List list1 = ["abc", "int", "hello"];
  const List list2 = [1, 2, 12];
  const List list3 = ["test"];

  List a = const [...list1];
  Expect.listEquals(["abc", "int", "hello"], a);

  a = const ["testme", ...list1];
  Expect.listEquals(["testme", "abc", "int", "hello"], a);

  a = const [...list1, "testme"];
  Expect.listEquals(["abc", "int", "hello", "testme"], a);

  a = const [...list1, ...list2, ...list3];
  Expect.listEquals(["abc", "int", "hello", 1, 2, 12, "test"], a);
}