| // 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 'package:source_span/source_span.dart'; |
| |
| import 'src/all.dart'; |
| import 'src/impl.dart'; |
| import 'src/none.dart'; |
| |
| /// A boolean expression that evaluates to `true` or `false` based on certain |
| /// inputs. |
| /// |
| /// The syntax is mostly Dart's expression syntax restricted to boolean |
| /// operations. See [the README][] for full details. |
| /// |
| /// [the README]: https://github.com/dart-lang/boolean_selector/blob/master/README.md |
| /// |
| /// Boolean selectors support structural equality. Two selectors that have the |
| /// same parsed structure are considered equal. |
| abstract class BooleanSelector { |
| /// A selector that accepts all inputs. |
| static const all = All(); |
| |
| /// A selector that accepts no inputs. |
| static const none = None(); |
| |
| /// All the variables in this selector, in the order they appear. |
| Iterable<String> get variables; |
| |
| /// Parses [selector]. |
| /// |
| /// This will throw a [SourceSpanFormatException] if the selector is |
| /// malformed or if it uses an undefined variable. |
| factory BooleanSelector.parse(String selector) = BooleanSelectorImpl.parse; |
| |
| /// Returns whether the selector matches the given [semantics]. |
| /// |
| /// The [semantics] define which variables evaluate to `true` or `false`. When |
| /// passed a variable name it should return the value of that variable. |
| bool evaluate(bool Function(String variable) semantics); |
| |
| /// Returns a new [BooleanSelector] that matches only inputs matched by both |
| /// [this] and [other]. |
| BooleanSelector intersection(BooleanSelector other); |
| |
| /// Returns a new [BooleanSelector] that matches all inputs matched by either |
| /// [this] or [other]. |
| BooleanSelector union(BooleanSelector other); |
| |
| /// Throws a [FormatException] if any variables are undefined. |
| /// |
| /// The [isDefined] function should return `true` for any variables that are |
| /// considered valid, and `false` for any invalid or undefined variables. |
| void validate(bool Function(String variable) isDefined); |
| } |