Scanner/parser support for DEP 9 (null-aware operators).

pkg/analyzer/test/generated/scanner_test.dart

 // Copyright (c) 2014, 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.
 
 library engine.scanner_test;
 
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 152 matching lines @@
       } else {
         // keyword.substring(0, keyword.length() - 1)
         expect(state, isNotNull);
       }
     }
   }
 }
 
 @reflectiveTest
 class ScannerTest {
+  /**
+   * If non-null, this value is used to override the default value of
+   * [Scanner.enableNullAwareOperators] before scanning.
+   */
+  bool _enableNullAwareOperators;
+
   void fail_incomplete_string_interpolation() {
     // https://code.google.com/p/dart/issues/detail?id=18073
     _assertErrorAndTokens(ScannerErrorCode.UNTERMINATED_STRING_LITERAL, 9,
         "\"foo \${bar", [
       new StringToken(TokenType.STRING, "\"foo ", 0),
       new StringToken(TokenType.STRING_INTERPOLATION_EXPRESSION, "\${", 5),
       new StringToken(TokenType.IDENTIFIER, "bar", 7)
     ]);
   }
 
@@ skipping 530 matching lines @@
   }
 
   void test_plus_plus() {
     _assertToken(TokenType.PLUS_PLUS, "++");
   }
 
   void test_question() {
     _assertToken(TokenType.QUESTION, "?");
   }
 
+  void test_question_dot() {
+    _enableNullAwareOperators = true;
+    _assertToken(TokenType.QUESTION_PERIOD, "?.");
+  }
+
+  void test_question_question() {
+    _enableNullAwareOperators = true;
+    _assertToken(TokenType.QUESTION_QUESTION, "??");
+  }
+
+  void test_question_question_eq() {
+    _enableNullAwareOperators = true;
+    _assertToken(TokenType.QUESTION_QUESTION_EQ, "??=");
+  }
+
   void test_scriptTag_withArgs() {
     _assertToken(TokenType.SCRIPT_TAG, "#!/bin/dart -debug");
   }
 
   void test_scriptTag_withoutSpace() {
     _assertToken(TokenType.SCRIPT_TAG, "#!/bin/dart");
   }
 
   void test_scriptTag_withSpace() {
     _assertToken(TokenType.SCRIPT_TAG, "#! /bin/dart");
@@ skipping 468 matching lines @@
   Token _scan(String source) {
     GatheringErrorListener listener = new GatheringErrorListener();
     Token token = _scanWithListener(source, listener);
     listener.assertNoErrors();
     return token;
   }
 
   Token _scanWithListener(String source, GatheringErrorListener listener) {
     Scanner scanner =
         new Scanner(null, new CharSequenceReader(source), listener);
+    if (_enableNullAwareOperators != null) {
+      scanner.enableNullAwareOperators = _enableNullAwareOperators;
+    }
     Token result = scanner.tokenize();
     listener.setLineInfo(new TestSource(), scanner.lineStarts);
     return result;
   }
 }
 
 /**
  * An `ExpectedLocation` encodes information about the expected location of a
  * given offset in source code.
  */
@@ skipping 134 matching lines @@
     expect(TokenType.LT_LT.isUserDefinableOperator, isTrue);
     expect(TokenType.MINUS.isUserDefinableOperator, isTrue);
     expect(TokenType.PERCENT.isUserDefinableOperator, isTrue);
     expect(TokenType.PLUS.isUserDefinableOperator, isTrue);
     expect(TokenType.SLASH.isUserDefinableOperator, isTrue);
     expect(TokenType.STAR.isUserDefinableOperator, isTrue);
     expect(TokenType.TILDE.isUserDefinableOperator, isTrue);
     expect(TokenType.TILDE_SLASH.isUserDefinableOperator, isTrue);
   }
 }