blob: 35970b51fc2aee839b5ddcd048287b4d106f8375 [file] [log] [blame]
// 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.
import '../boolean_selector.dart';
/// A selector that matches no inputs.
class None implements BooleanSelector {
final variables = const [];
const None();
bool evaluate(semantics) => false;
BooleanSelector intersection(BooleanSelector other) => this;
BooleanSelector union(BooleanSelector other) => other;
void validate(bool isDefined(String variable)) {}
String toString() => "<none>";