| // Copyright (c) 2017, 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 'visitors.dart'; |
| |
| abstract class Spec { |
| R accept<R>(SpecVisitor<R> visitor, [R? context]); |
| } |
| |
| /// Returns a generic [Spec] that is lazily generated when visited. |
| Spec lazySpec(Spec Function() generate) => _LazySpec(generate); |
| |
| class _LazySpec implements Spec { |
| final Spec Function() generate; |
| |
| const _LazySpec(this.generate); |
| |
| @override |
| R accept<R>(SpecVisitor<R> visitor, [R? context]) => |
| generate().accept(visitor, context); |
| } |