Initial implementation for lazy compound assignment 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 analyzer.test.generated.scanner_test;
 
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
@@ skipping 174 matching lines @@
   }
 
   void test_ampersand() {
     _assertToken(TokenType.AMPERSAND, "&");
   }
 
   void test_ampersand_ampersand() {
     _assertToken(TokenType.AMPERSAND_AMPERSAND, "&&");
   }
 
+  void test_ampersand_ampersand_eq() {
+    _assertToken(TokenType.AMPERSAND_AMPERSAND_EQ, "&&=",
+        lazyAssignmentOperators: true);
+  }
+
   void test_ampersand_eq() {
     _assertToken(TokenType.AMPERSAND_EQ, "&=");
   }
 
   void test_at() {
     _assertToken(TokenType.AT, "@");
   }
 
   void test_backping() {
     _assertToken(TokenType.BACKPING, "`");
@@ skipping 12 matching lines @@
   }
 
   void test_bar() {
     _assertToken(TokenType.BAR, "|");
   }
 
   void test_bar_bar() {
     _assertToken(TokenType.BAR_BAR, "||");
   }
 
+  void test_bar_bar_eq() {
+    _assertToken(TokenType.BAR_BAR_EQ, "||=", lazyAssignmentOperators: true);
+  }
+
   void test_bar_eq() {
     _assertToken(TokenType.BAR_EQ, "|=");
   }
 
   void test_caret() {
     _assertToken(TokenType.CARET, "^");
   }
 
   void test_caret_eq() {
     _assertToken(TokenType.CARET_EQ, "^=");
@@ skipping 933 matching lines @@
           reason: 'Line number in location $i');
       expect(location.columnNumber, expectedLocation._columnNumber,
           reason: 'Column number in location $i');
     }
   }
 
   /**
    * Assert that the token scanned from the given [source] has the
    * [expectedType].
    */
-  Token _assertToken(TokenType expectedType, String source) {
-    Token originalToken = _scan(source);
+  Token _assertToken(TokenType expectedType, String source,
+      {bool lazyAssignmentOperators: false}) {
+    Token originalToken =
+        _scan(source, lazyAssignmentOperators: lazyAssignmentOperators);
     expect(originalToken, isNotNull);
     expect(originalToken.type, expectedType);
     expect(originalToken.offset, 0);
     expect(originalToken.length, source.length);
     expect(originalToken.lexeme, source);
     if (expectedType == TokenType.SCRIPT_TAG) {
       // Adding space before the script tag is not allowed, and adding text at
       // the end changes nothing.
       return originalToken;
     } else if (expectedType == TokenType.SINGLE_LINE_COMMENT) {
       // Adding space to an end-of-line comment changes the comment.
-      Token tokenWithSpaces = _scan(" $source");
+      Token tokenWithSpaces =
+          _scan(" $source", lazyAssignmentOperators: lazyAssignmentOperators);
       expect(tokenWithSpaces, isNotNull);
       expect(tokenWithSpaces.type, expectedType);
       expect(tokenWithSpaces.offset, 1);
       expect(tokenWithSpaces.length, source.length);
       expect(tokenWithSpaces.lexeme, source);
       return originalToken;
     } else if (expectedType == TokenType.INT ||
         expectedType == TokenType.DOUBLE) {
-      Token tokenWithLowerD = _scan("${source}d");
+      Token tokenWithLowerD =
+          _scan("${source}d", lazyAssignmentOperators: lazyAssignmentOperators);
       expect(tokenWithLowerD, isNotNull);
       expect(tokenWithLowerD.type, expectedType);
       expect(tokenWithLowerD.offset, 0);
       expect(tokenWithLowerD.length, source.length);
       expect(tokenWithLowerD.lexeme, source);
-      Token tokenWithUpperD = _scan("${source}D");
+      Token tokenWithUpperD =
+          _scan("${source}D", lazyAssignmentOperators: lazyAssignmentOperators);
       expect(tokenWithUpperD, isNotNull);
       expect(tokenWithUpperD.type, expectedType);
       expect(tokenWithUpperD.offset, 0);
       expect(tokenWithUpperD.length, source.length);
       expect(tokenWithUpperD.lexeme, source);
     }
-    Token tokenWithSpaces = _scan(" $source ");
+    Token tokenWithSpaces =
+        _scan(" $source ", lazyAssignmentOperators: lazyAssignmentOperators);
     expect(tokenWithSpaces, isNotNull);
     expect(tokenWithSpaces.type, expectedType);
     expect(tokenWithSpaces.offset, 1);
     expect(tokenWithSpaces.length, source.length);
     expect(tokenWithSpaces.lexeme, source);
     expect(originalToken.next.type, TokenType.EOF);
     return originalToken;
   }
 
   /**
@@ skipping 16 matching lines @@
       expect(token.length, expectedToken.length,
           reason: "Wrong length for token $i");
       expect(token.lexeme, expectedToken.lexeme,
           reason: "Wrong lexeme for token $i");
       token = token.next;
       expect(token, isNotNull);
     }
     expect(token.type, TokenType.EOF);
   }
 
-  Token _scan(String source, {bool genericMethodComments: false}) {
+  Token _scan(String source,
+      {bool genericMethodComments: false,
+      bool lazyAssignmentOperators: false}) {
     GatheringErrorListener listener = new GatheringErrorListener();
     Token token = _scanWithListener(source, listener,
-        genericMethodComments: genericMethodComments);
+        genericMethodComments: genericMethodComments,
+        lazyAssignmentOperators: lazyAssignmentOperators);
     listener.assertNoErrors();
     return token;
   }
 
   Token _scanWithListener(String source, GatheringErrorListener listener,
-      {bool genericMethodComments: false}) {
+      {bool genericMethodComments: false,
+      bool lazyAssignmentOperators: false}) {
     Scanner scanner =
         new Scanner(null, new CharSequenceReader(source), listener);
-    if (genericMethodComments) {
-      scanner.scanGenericMethodComments = true;
-    }
+    scanner.scanGenericMethodComments = genericMethodComments;
+    scanner.scanLazyAssignmentOperators = lazyAssignmentOperators;
     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);
   }
 }