Index: lib/src/none.dart |
diff --git a/lib/src/none.dart b/lib/src/none.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..35970b51fc2aee839b5ddcd048287b4d106f8375 |
--- /dev/null |
+++ b/lib/src/none.dart |
@@ -0,0 +1,22 @@ |
+// 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>"; |
+} |