LanguageFeatures/Patterns/invocation_keys_A04_t03.dart

// Copyright (c) 2023, 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 At runtime, whenever the runtime semantics say to call a member
/// or access a record field, if a previous call or access with that same
/// invocation key has already been evaluated, we reuse the result.
/// ...
/// Given a set of patterns s matching a value expression v, we bind an
/// invocation key to each member invocation and record field access in s like
/// so:
/// 1. Let i be an invocation key with no parent, no extension type, named this,
///   with an empty argument list. This is the root node of the invocation key
///   tree and represents the matched value itself.
/// 2. For each pattern p in s with parent invocation i, bind invocation keys to
///   it and its subpatterns using the following procedure:
/// To bind invocation keys in a pattern p using parent invocation i:
/// ...
/// Cast, null-check, null-assert, or parenthesized:
/// i. Bind invocations in the subpattern using parent i.
///
/// @description Checks that invocation key of a null-assert pattern is a key of
/// its subpattern
/// @author sgrekhov22@gmail.com

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

String test1(Object o) {
  switch (o) {
    case [var x!, 1]: // Expect calls [0], [1] (`length` is not logged)
      return "match-1";
    case [1, var x!]: // Expect no new calls
      return "match-2";
    default:
      return "no match";
  }
}

String test2(Object o) =>
  switch (o) {
    [var x!, 1] => "match-1",
    [1, var x!] => "match-2",
    _ => "no match"
  };

main() {
  final ml = MyList<int>([1, 2], logLength: false);
  Expect.equals("match-2", test1(ml));
  Expect.equals("[0];[1];", ml.log);
  ml.clearLog();

  Expect.equals("match-2", test2(ml));
  Expect.equals("[0];[1];", ml.log);
}