Move scanner into pkg/front_end/lib/src/scanner.

pkg/analyzer/lib/src/dart/scanner/scanner.dart

Index: pkg/analyzer/lib/src/dart/scanner/scanner.dart
diff --git a/pkg/analyzer/lib/src/dart/scanner/scanner.dart b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
index 3c74e78ba79590e9d4d57504e90ae8e755bc6f60..3f87b847852dd11094caa3fbd2395093ac6571a1 100644
--- a/pkg/analyzer/lib/src/dart/scanner/scanner.dart
+++ b/pkg/analyzer/lib/src/dart/scanner/scanner.dart
@@ -4,123 +4,15 @@
 
 library analyzer.src.dart.scanner.scanner;
 
-import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
-import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
-import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/source.dart';
-import 'package:charcode/ascii.dart';
+import 'package:front_end/src/scanner/scanner.dart' as fe;
 
 export 'package:analyzer/src/dart/error/syntactic_errors.dart';
-
-/**
- * A state in a state machine used to scan keywords.
- */
-class KeywordState {
-  /**
-   * An empty transition table used by leaf states.
-   */
-  static List<KeywordState> _EMPTY_TABLE = new List<KeywordState>(26);
-
-  /**
-   * The initial state in the state machine.
-   */
-  static final KeywordState KEYWORD_STATE = _createKeywordStateTable();
-
-  /**
-   * A table mapping characters to the states to which those characters will
-   * transition. (The index into the array is the offset from the character
-   * `'a'` to the transitioning character.)
-   */
-  final List<KeywordState> _table;
-
-  /**
-   * The keyword that is recognized by this state, or `null` if this state is
-   * not a terminal state.
-   */
-  Keyword _keyword;
-
-  /**
-   * Initialize a newly created state to have the given transitions and to
-   * recognize the keyword with the given [syntax].
-   */
-  KeywordState(this._table, String syntax) {
-    this._keyword = (syntax == null) ? null : Keyword.keywords[syntax];
-  }
-
-  /**
-   * Return the keyword that was recognized by this state, or `null` if this
-   * state does not recognized a keyword.
-   */
-  Keyword keyword() => _keyword;
-
-  /**
-   * Return the state that follows this state on a transition of the given
-   * [character], or `null` if there is no valid state reachable from this state
-   * with such a transition.
-   */
-  KeywordState next(int character) => _table[character - $a];
-
-  /**
-   * Create the next state in the state machine where we have already recognized
-   * the subset of strings in the given array of [strings] starting at the given
-   * [offset] and having the given [length]. All of these strings have a common
-   * prefix and the next character is at the given [start] index.
-   */
-  static KeywordState _computeKeywordStateTable(
-      int start, List<String> strings, int offset, int length) {
-    List<KeywordState> result = new List<KeywordState>(26);
-    assert(length != 0);
-    int chunk = $nul;
-    int chunkStart = -1;
-    bool isLeaf = false;
-    for (int i = offset; i < offset + length; i++) {
-      if (strings[i].length == start) {
-        isLeaf = true;
-      }
-      if (strings[i].length > start) {
-        int c = strings[i].codeUnitAt(start);
-        if (chunk != c) {
-          if (chunkStart != -1) {
-            result[chunk - $a] = _computeKeywordStateTable(
-                start + 1, strings, chunkStart, i - chunkStart);
-          }
-          chunkStart = i;
-          chunk = c;
-        }
-      }
-    }
-    if (chunkStart != -1) {
-      assert(result[chunk - $a] == null);
-      result[chunk - $a] = _computeKeywordStateTable(
-          start + 1, strings, chunkStart, offset + length - chunkStart);
-    } else {
-      assert(length == 1);
-      return new KeywordState(_EMPTY_TABLE, strings[offset]);
-    }
-    if (isLeaf) {
-      return new KeywordState(result, strings[offset]);
-    } else {
-      return new KeywordState(result, null);
-    }
-  }
-
-  /**
-   * Create and return the initial state in the state machine.
-   */
-  static KeywordState _createKeywordStateTable() {
-    List<Keyword> values = Keyword.values;
-    List<String> strings = new List<String>(values.length);
-    for (int i = 0; i < values.length; i++) {
-      strings[i] = values[i].syntax;
-    }
-    strings.sort();
-    return _computeKeywordStateTable(0, strings, 0, strings.length);
-  }
-}
+export 'package:front_end/src/scanner/scanner.dart' show KeywordState;
 
 /**
  * The class `Scanner` implements a scanner for Dart code.
@@ -132,1224 +24,31 @@ class KeywordState {
  * any context, so it always resolves such conflicts by scanning the longest
  * possible token.
  */
-class Scanner {
+class Scanner extends fe.Scanner {
   /**
    * The source being scanned.
    */
   final Source source;
 
   /**
-   * The reader used to access the characters in the source.
-   */
-  final CharacterReader _reader;
-
-  /**
    * The error listener that will be informed of any errors that are found
    * during the scan.
    */
   final AnalysisErrorListener _errorListener;
 
   /**
-   * The flag specifying whether documentation comments should be parsed.
-   */
-  bool _preserveComments = true;
-
-  /**
-   * The token pointing to the head of the linked list of tokens.
-   */
-  Token _tokens;
-
-  /**
-   * The last token that was scanned.
-   */
-  Token _tail;
-
-  /**
-   * The first token in the list of comment tokens found since the last
-   * non-comment token.
-   */
-  Token _firstComment;
-
-  /**
-   * The last token in the list of comment tokens found since the last
-   * non-comment token.
-   */
-  Token _lastComment;
-
-  /**
-   * The index of the first character of the current token.
-   */
-  int _tokenStart = 0;
-
-  /**
-   * A list containing the offsets of the first character of each line in the
-   * source code.
-   */
-  List<int> _lineStarts = new List<int>();
-
-  /**
-   * A list, treated something like a stack, of tokens representing the
-   * beginning of a matched pair. It is used to pair the end tokens with the
-   * begin tokens.
-   */
-  List<BeginToken> _groupingStack = new List<BeginToken>();
-
-  /**
-   * The index of the last item in the [_groupingStack], or `-1` if the stack is
-   * empty.
-   */
-  int _stackEnd = -1;
-
-  /**
-   * A flag indicating whether any unmatched groups were found during the parse.
-   */
-  bool _hasUnmatchedGroups = false;
-
-  /**
-   * A flag indicating whether to parse generic method comments, of the form
-   * `/*=T*/` and `/*<T>*/`.
-   */
-  bool scanGenericMethodComments = false;
-
-  /**
-   * A flag indicating whether the lazy compound assignment operators '&&=' and
-   * '||=' are enabled.
-   */
-  bool scanLazyAssignmentOperators = false;
-
-  /**
    * Initialize a newly created scanner to scan characters from the given
-   * [source]. The given character [_reader] will be used to read the characters
+   * [source]. The given character [reader] will be used to read the characters
    * in the source. The given [_errorListener] will be informed of any errors
    * that are found.
    */
-  Scanner(this.source, this._reader, this._errorListener) {
-    _tokens = new Token(TokenType.EOF, -1);
-    _tokens.setNext(_tokens);
-    _tail = _tokens;
-    _tokenStart = -1;
-    _lineStarts.add(0);
-  }
-
-  /**
-   * Return the first token in the token stream that was scanned.
-   */
-  Token get firstToken => _tokens.next;
-
-  /**
-   * Return `true` if any unmatched groups were found during the parse.
-   */
-  bool get hasUnmatchedGroups => _hasUnmatchedGroups;
-
-  /**
-   * Return an array containing the offsets of the first character of each line
-   * in the source code.
-   */
-  List<int> get lineStarts => _lineStarts;
-
-  /**
-   * Set whether documentation tokens should be preserved.
-   */
-  void set preserveComments(bool preserveComments) {
-    this._preserveComments = preserveComments;
-  }
-
-  /**
-   * Return the last token that was scanned.
-   */
-  Token get tail => _tail;
-
-  /**
-   * Append the given [token] to the end of the token stream being scanned. This
-   * method is intended to be used by subclasses that copy existing tokens and
-   * should not normally be used because it will fail to correctly associate any
-   * comments with the token being passed in.
-   */
-  void appendToken(Token token) {
-    _tail = _tail.setNext(token);
-  }
-
-  int bigSwitch(int next) {
-    _beginToken();
-    if (next == $cr) {
-      // '\r'
-      next = _reader.advance();
-      if (next == $lf) {
-        // '\n'
-        next = _reader.advance();
-      }
-      recordStartOfLine();
-      return next;
-    } else if (next == $lf) {
-      // '\n'
-      next = _reader.advance();
-      recordStartOfLine();
-      return next;
-    } else if (next == $tab || next == $space) {
-      // '\t' || ' '
-      return _reader.advance();
-    }
-    if (next == $r) {
-      // 'r'
-      int peek = _reader.peek();
-      if (peek == $double_quote || peek == $single_quote) {
-        // '"' || "'"
-        int start = _reader.offset;
-        return _tokenizeString(_reader.advance(), start, true);
-      }
-    }
-    if ($a <= next && next <= $z) {
-      // 'a'-'z'
-      return _tokenizeKeywordOrIdentifier(next, true);
-    }
-    if (($A <= next && next <= $Z) || next == $_ || next == $$) {
-      // 'A'-'Z' || '_' || '$'
-      return _tokenizeIdentifier(next, _reader.offset, true);
-    }
-    if (next == $lt) {
-      // '<'
-      return _tokenizeLessThan(next);
-    }
-    if (next == $gt) {
-      // '>'
-      return _tokenizeGreaterThan(next);
-    }
-    if (next == $equal) {
-      // '='
-      return _tokenizeEquals(next);
-    }
-    if (next == $exclamation) {
-      // '!'
-      return _tokenizeExclamation(next);
-    }
-    if (next == $plus) {
-      // '+'
-      return _tokenizePlus(next);
-    }
-    if (next == $minus) {
-      // '-'
-      return _tokenizeMinus(next);
-    }
-    if (next == $asterisk) {
-      // '*'
-      return _tokenizeMultiply(next);
-    }
-    if (next == $percent) {
-      // '%'
-      return _tokenizePercent(next);
-    }
-    if (next == $ampersand) {
-      // '&'
-      return _tokenizeAmpersand(next);
-    }
-    if (next == $bar) {
-      // '|'
-      return _tokenizeBar(next);
-    }
-    if (next == $caret) {
-      // '^'
-      return _tokenizeCaret(next);
-    }
-    if (next == $open_bracket) {
-      // '['
-      return _tokenizeOpenSquareBracket(next);
-    }
-    if (next == $tilde) {
-      // '~'
-      return _tokenizeTilde(next);
-    }
-    if (next == $backslash) {
-      // '\\'
-      _appendTokenOfType(TokenType.BACKSLASH);
-      return _reader.advance();
-    }
-    if (next == $hash) {
-      // '#'
-      return _tokenizeTag(next);
-    }
-    if (next == $open_paren) {
-      // '('
-      _appendBeginToken(TokenType.OPEN_PAREN);
-      return _reader.advance();
-    }
-    if (next == $close_paren) {
-      // ')'
-      _appendEndToken(TokenType.CLOSE_PAREN, TokenType.OPEN_PAREN);
-      return _reader.advance();
-    }
-    if (next == $comma) {
-      // ','
-      _appendTokenOfType(TokenType.COMMA);
-      return _reader.advance();
-    }
-    if (next == $colon) {
-      // ':'
-      _appendTokenOfType(TokenType.COLON);
-      return _reader.advance();
-    }
-    if (next == $semicolon) {
-      // ';'
-      _appendTokenOfType(TokenType.SEMICOLON);
-      return _reader.advance();
-    }
-    if (next == $question) {
-      // '?'
-      return _tokenizeQuestion();
-    }
-    if (next == $close_bracket) {
-      // ']'
-      _appendEndToken(
-          TokenType.CLOSE_SQUARE_BRACKET, TokenType.OPEN_SQUARE_BRACKET);
-      return _reader.advance();
-    }
-    if (next == $backquote) {
-      // '`'
-      _appendTokenOfType(TokenType.BACKPING);
-      return _reader.advance();
-    }
-    if (next == $lbrace) {
-      // '{'
-      _appendBeginToken(TokenType.OPEN_CURLY_BRACKET);
-      return _reader.advance();
-    }
-    if (next == $rbrace) {
-      // '}'
-      _appendEndToken(
-          TokenType.CLOSE_CURLY_BRACKET, TokenType.OPEN_CURLY_BRACKET);
-      return _reader.advance();
-    }
-    if (next == $slash) {
-      // '/'
-      return _tokenizeSlashOrComment(next);
-    }
-    if (next == $at) {
-      // '@'
-      _appendTokenOfType(TokenType.AT);
-      return _reader.advance();
-    }
-    if (next == $double_quote || next == $single_quote) {
-      // '"' || "'"
-      return _tokenizeString(next, _reader.offset, false);
-    }
-    if (next == $dot) {
-      // '.'
-      return _tokenizeDotOrNumber(next);
-    }
-    if (next == $0) {
-      // '0'
-      return _tokenizeHexOrNumber(next);
-    }
-    if ($1 <= next && next <= $9) {
-      // '1'-'9'
-      return _tokenizeNumber(next);
-    }
-    if (next == -1) {
-      // EOF
-      return -1;
-    }
-    _reportError(ScannerErrorCode.ILLEGAL_CHARACTER, [next]);
-    return _reader.advance();
-  }
-
-  /**
-   * Record the fact that we are at the beginning of a new line in the source.
-   */
-  void recordStartOfLine() {
-    _lineStarts.add(_reader.offset);
-  }
-
-  /**
-   * Record that the source begins on the given [line] and [column] at the
-   * current offset as given by the reader. Both the line and the column are
-   * one-based indexes. The line starts for lines before the given line will not
-   * be correct.
-   *
-   * This method must be invoked at most one time and must be invoked before
-   * scanning begins. The values provided must be sensible. The results are
-   * undefined if these conditions are violated.
-   */
-  void setSourceStart(int line, int column) {
-    int offset = _reader.offset;
-    if (line < 1 || column < 1 || offset < 0 || (line + column - 2) >= offset) {
-      return;
-    }
-    for (int i = 2; i < line; i++) {
-      _lineStarts.add(1);
-    }
-    _lineStarts.add(offset - column + 1);
-  }
-
-  /**
-   * Scan the source code to produce a list of tokens representing the source,
-   * and return the first token in the list of tokens that were produced.
-   */
-  Token tokenize() {
-    int next = _reader.advance();
-    while (next != -1) {
-      next = bigSwitch(next);
-    }
-    _appendEofToken();
-    return firstToken;
-  }
-
-  void _appendBeginToken(TokenType type) {
-    BeginToken token;
-    if (_firstComment == null) {
-      token = new BeginToken(type, _tokenStart);
-    } else {
-      token = new BeginTokenWithComment(type, _tokenStart, _firstComment);
-      _firstComment = null;
-      _lastComment = null;
-    }
-    _tail = _tail.setNext(token);
-    _groupingStack.add(token);
-    _stackEnd++;
-  }
-
-  void _appendCommentToken(TokenType type, String value) {
-    CommentToken token = null;
-    TokenType genericComment = _matchGenericMethodCommentType(value);
-    if (genericComment != null) {
-      token = new CommentToken(genericComment, value, _tokenStart);
-    } else if (!_preserveComments) {
-      // Ignore comment tokens if client specified that it doesn't need them.
-      return;
-    } else {
-      // OK, remember comment tokens.
-      if (_isDocumentationComment(value)) {
-        token = new DocumentationCommentToken(type, value, _tokenStart);
-      } else {
-        token = new CommentToken(type, value, _tokenStart);
-      }
-    }
-    if (_firstComment == null) {
-      _firstComment = token;
-      _lastComment = _firstComment;
-    } else {
-      _lastComment = _lastComment.setNext(token);
-    }
-  }
-
-  void _appendEndToken(TokenType type, TokenType beginType) {
-    Token token;
-    if (_firstComment == null) {
-      token = new Token(type, _tokenStart);
-    } else {
-      token = new TokenWithComment(type, _tokenStart, _firstComment);
-      _firstComment = null;
-      _lastComment = null;
-    }
-    _tail = _tail.setNext(token);
-    if (_stackEnd >= 0) {
-      BeginToken begin = _groupingStack[_stackEnd];
-      if (begin.type == beginType) {
-        begin.endToken = token;
-        _groupingStack.removeAt(_stackEnd--);
-      }
-    }
-  }
-
-  void _appendEofToken() {
-    Token eofToken;
-    if (_firstComment == null) {
-      eofToken = new Token(TokenType.EOF, _reader.offset + 1);
-    } else {
-      eofToken = new TokenWithComment(
-          TokenType.EOF, _reader.offset + 1, _firstComment);
-      _firstComment = null;
-      _lastComment = null;
-    }
-    // The EOF token points to itself so that there is always infinite
-    // look-ahead.
-    eofToken.setNext(eofToken);
-    _tail = _tail.setNext(eofToken);
-    if (_stackEnd >= 0) {
-      _hasUnmatchedGroups = true;
-      // TODO(brianwilkerson) Fix the ungrouped tokens?
-    }
-  }
-
-  void _appendKeywordToken(Keyword keyword) {
-    if (_firstComment == null) {
-      _tail = _tail.setNext(new KeywordToken(keyword, _tokenStart));
-    } else {
-      _tail = _tail.setNext(
-          new KeywordTokenWithComment(keyword, _tokenStart, _firstComment));
-      _firstComment = null;
-      _lastComment = null;
-    }
-  }
-
-  void _appendStringToken(TokenType type, String value) {
-    if (_firstComment == null) {
-      _tail = _tail.setNext(new StringToken(type, value, _tokenStart));
-    } else {
-      _tail = _tail.setNext(
-          new StringTokenWithComment(type, value, _tokenStart, _firstComment));
-      _firstComment = null;
-      _lastComment = null;
-    }
-  }
-
-  void _appendStringTokenWithOffset(TokenType type, String value, int offset) {
-    if (_firstComment == null) {
-      _tail = _tail.setNext(new StringToken(type, value, _tokenStart + offset));
-    } else {
-      _tail = _tail.setNext(new StringTokenWithComment(
-          type, value, _tokenStart + offset, _firstComment));
-      _firstComment = null;
-      _lastComment = null;
-    }
-  }
-
-  void _appendTokenOfType(TokenType type) {
-    if (_firstComment == null) {
-      _tail = _tail.setNext(new Token(type, _tokenStart));
-    } else {
-      _tail =
-          _tail.setNext(new TokenWithComment(type, _tokenStart, _firstComment));
-      _firstComment = null;
-      _lastComment = null;
-    }
-  }
-
-  void _appendTokenOfTypeWithOffset(TokenType type, int offset) {
-    if (_firstComment == null) {
-      _tail = _tail.setNext(new Token(type, offset));
-    } else {
-      _tail = _tail.setNext(new TokenWithComment(type, offset, _firstComment));
-      _firstComment = null;
-      _lastComment = null;
-    }
-  }
-
-  void _beginToken() {
-    _tokenStart = _reader.offset;
-  }
-
-  /**
-   * Return the beginning token corresponding to a closing brace that was found
-   * while scanning inside a string interpolation expression. Tokens that cannot
-   * be matched with the closing brace will be dropped from the stack.
-   */
-  BeginToken _findTokenMatchingClosingBraceInInterpolationExpression() {
-    while (_stackEnd >= 0) {
-      BeginToken begin = _groupingStack[_stackEnd];
-      if (begin.type == TokenType.OPEN_CURLY_BRACKET ||
-          begin.type == TokenType.STRING_INTERPOLATION_EXPRESSION) {
-        return begin;
-      }
-      _hasUnmatchedGroups = true;
-      _groupingStack.removeAt(_stackEnd--);
-    }
-    //
-    // We should never get to this point because we wouldn't be inside a string
-    // interpolation expression unless we had previously found the start of the
-    // expression.
-    //
-    return null;
-  }
-
-  /**
-   * Checks if [value] is the start of a generic method type annotation comment.
-   *
-   * This can either be of the form `/*<T>*/` or `/*=T*/`. The token type is
-   * returned, or null if it was not a generic method comment.
-   */
-  TokenType _matchGenericMethodCommentType(String value) {
-    if (scanGenericMethodComments) {
-      // Match /*< and >*/
-      if (StringUtilities.startsWith3(value, 0, $slash, $asterisk, $lt) &&
-          StringUtilities.endsWith3(value, $gt, $asterisk, $slash)) {
-        return TokenType.GENERIC_METHOD_TYPE_LIST;
-      }
-      // Match /*=
-      if (StringUtilities.startsWith3(value, 0, $slash, $asterisk, $equal)) {
-        return TokenType.GENERIC_METHOD_TYPE_ASSIGN;
-      }
-    }
-    return null;
-  }
-
-  /**
-   * Report an error at the current offset. The [errorCode] is the error code
-   * indicating the nature of the error. The [arguments] are any arguments
-   * needed to complete the error message
-   */
-  void _reportError(ScannerErrorCode errorCode, [List<Object> arguments]) {
-    _errorListener.onError(
-        new AnalysisError(source, _reader.offset, 1, errorCode, arguments));
-  }
-
-  int _select(int choice, TokenType yesType, TokenType noType) {
-    int next = _reader.advance();
-    if (next == choice) {
-      _appendTokenOfType(yesType);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(noType);
-      return next;
-    }
-  }
-
-  int _selectWithOffset(
-      int choice, TokenType yesType, TokenType noType, int offset) {
-    int next = _reader.advance();
-    if (next == choice) {
-      _appendTokenOfTypeWithOffset(yesType, offset);
-      return _reader.advance();
-    } else {
-      _appendTokenOfTypeWithOffset(noType, offset);
-      return next;
-    }
-  }
-
-  int _tokenizeAmpersand(int next) {
-    // &&= && &= &
-    next = _reader.advance();
-    if (next == $ampersand) {
-      next = _reader.advance();
-      if (scanLazyAssignmentOperators && next == $equal) {
-        _appendTokenOfType(TokenType.AMPERSAND_AMPERSAND_EQ);
-        return _reader.advance();
-      }
-      _appendTokenOfType(TokenType.AMPERSAND_AMPERSAND);
-      return next;
-    } else if (next == $equal) {
-      _appendTokenOfType(TokenType.AMPERSAND_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.AMPERSAND);
-      return next;
-    }
-  }
-
-  int _tokenizeBar(int next) {
-    // ||= || |= |
-    next = _reader.advance();
-    if (next == $bar) {
-      next = _reader.advance();
-      if (scanLazyAssignmentOperators && next == $equal) {
-        _appendTokenOfType(TokenType.BAR_BAR_EQ);
-        return _reader.advance();
-      }
-      _appendTokenOfType(TokenType.BAR_BAR);
-      return next;
-    } else if (next == $equal) {
-      _appendTokenOfType(TokenType.BAR_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.BAR);
-      return next;
-    }
-  }
-
-  int _tokenizeCaret(int next) =>
-      _select($equal, TokenType.CARET_EQ, TokenType.CARET);
-
-  int _tokenizeDotOrNumber(int next) {
-    int start = _reader.offset;
-    next = _reader.advance();
-    if ($0 <= next && next <= $9) {
-      return _tokenizeFractionPart(next, start);
-    } else if ($dot == next) {
-      return _select(
-          $dot, TokenType.PERIOD_PERIOD_PERIOD, TokenType.PERIOD_PERIOD);
-    } else {
-      _appendTokenOfType(TokenType.PERIOD);
-      return next;
-    }
-  }
-
-  int _tokenizeEquals(int next) {
-    // = == =>
-    next = _reader.advance();
-    if (next == $equal) {
-      _appendTokenOfType(TokenType.EQ_EQ);
-      return _reader.advance();
-    } else if (next == $gt) {
-      _appendTokenOfType(TokenType.FUNCTION);
-      return _reader.advance();
-    }
-    _appendTokenOfType(TokenType.EQ);
-    return next;
-  }
-
-  int _tokenizeExclamation(int next) {
-    // ! !=
-    next = _reader.advance();
-    if (next == $equal) {
-      _appendTokenOfType(TokenType.BANG_EQ);
-      return _reader.advance();
-    }
-    _appendTokenOfType(TokenType.BANG);
-    return next;
-  }
-
-  int _tokenizeExponent(int next) {
-    if (next == $plus || next == $minus) {
-      next = _reader.advance();
-    }
-    bool hasDigits = false;
-    while (true) {
-      if ($0 <= next && next <= $9) {
-        hasDigits = true;
-      } else {
-        if (!hasDigits) {
-          _reportError(ScannerErrorCode.MISSING_DIGIT);
-        }
-        return next;
-      }
-      next = _reader.advance();
-    }
-  }
-
-  int _tokenizeFractionPart(int next, int start) {
-    bool done = false;
-    bool hasDigit = false;
-    LOOP:
-    while (!done) {
-      if ($0 <= next && next <= $9) {
-        hasDigit = true;
-      } else if ($e == next || $E == next) {
-        hasDigit = true;
-        next = _tokenizeExponent(_reader.advance());
-        done = true;
-        continue LOOP;
-      } else {
-        done = true;
-        continue LOOP;
-      }
-      next = _reader.advance();
-    }
-    if (!hasDigit) {
-      _appendStringToken(TokenType.INT, _reader.getString(start, -2));
-      if ($dot == next) {
-        return _selectWithOffset($dot, TokenType.PERIOD_PERIOD_PERIOD,
-            TokenType.PERIOD_PERIOD, _reader.offset - 1);
-      }
-      _appendTokenOfTypeWithOffset(TokenType.PERIOD, _reader.offset - 1);
-      return bigSwitch(next);
-    }
-    _appendStringToken(
-        TokenType.DOUBLE, _reader.getString(start, next < 0 ? 0 : -1));
-    return next;
-  }
+  Scanner(this.source, CharacterReader reader, this._errorListener)
+      : super(reader);
 
-  int _tokenizeGreaterThan(int next) {
-    // > >= >> >>=
-    next = _reader.advance();
-    if ($equal == next) {
-      _appendTokenOfType(TokenType.GT_EQ);
-      return _reader.advance();
-    } else if ($gt == next) {
-      next = _reader.advance();
-      if ($equal == next) {
-        _appendTokenOfType(TokenType.GT_GT_EQ);
-        return _reader.advance();
-      } else {
-        _appendTokenOfType(TokenType.GT_GT);
-        return next;
-      }
-    } else {
-      _appendTokenOfType(TokenType.GT);
-      return next;
-    }
-  }
-
-  int _tokenizeHex(int next) {
-    int start = _reader.offset - 1;
-    bool hasDigits = false;
-    while (true) {
-      next = _reader.advance();
-      if (($0 <= next && next <= $9) ||
-          ($A <= next && next <= $F) ||
-          ($a <= next && next <= $f)) {
-        hasDigits = true;
-      } else {
-        if (!hasDigits) {
-          _reportError(ScannerErrorCode.MISSING_HEX_DIGIT);
-        }
-        _appendStringToken(
-            TokenType.HEXADECIMAL, _reader.getString(start, next < 0 ? 0 : -1));
-        return next;
-      }
-    }
-  }
-
-  int _tokenizeHexOrNumber(int next) {
-    int x = _reader.peek();
-    if (x == $x || x == $X) {
-      _reader.advance();
-      return _tokenizeHex(x);
-    }
-    return _tokenizeNumber(next);
-  }
-
-  int _tokenizeIdentifier(int next, int start, bool allowDollar) {
-    while (($a <= next && next <= $z) ||
-        ($A <= next && next <= $Z) ||
-        ($0 <= next && next <= $9) ||
-        next == $_ ||
-        (next == $$ && allowDollar)) {
-      next = _reader.advance();
-    }
-    _appendStringToken(
-        TokenType.IDENTIFIER, _reader.getString(start, next < 0 ? 0 : -1));
-    return next;
-  }
-
-  int _tokenizeInterpolatedExpression(int next, int start) {
-    _appendBeginToken(TokenType.STRING_INTERPOLATION_EXPRESSION);
-    next = _reader.advance();
-    while (next != -1) {
-      if (next == $rbrace) {
-        BeginToken begin =
-            _findTokenMatchingClosingBraceInInterpolationExpression();
-        if (begin == null) {
-          _beginToken();
-          _appendTokenOfType(TokenType.CLOSE_CURLY_BRACKET);
-          next = _reader.advance();
-          _beginToken();
-          return next;
-        } else if (begin.type == TokenType.OPEN_CURLY_BRACKET) {
-          _beginToken();
-          _appendEndToken(
-              TokenType.CLOSE_CURLY_BRACKET, TokenType.OPEN_CURLY_BRACKET);
-          next = _reader.advance();
-          _beginToken();
-        } else if (begin.type == TokenType.STRING_INTERPOLATION_EXPRESSION) {
-          _beginToken();
-          _appendEndToken(TokenType.CLOSE_CURLY_BRACKET,
-              TokenType.STRING_INTERPOLATION_EXPRESSION);
-          next = _reader.advance();
-          _beginToken();
-          return next;
-        }
-      } else {
-        next = bigSwitch(next);
-      }
-    }
-    return next;
-  }
-
-  int _tokenizeInterpolatedIdentifier(int next, int start) {
-    _appendStringTokenWithOffset(
-        TokenType.STRING_INTERPOLATION_IDENTIFIER, "\$", 0);
-    if (($A <= next && next <= $Z) ||
-        ($a <= next && next <= $z) ||
-        next == $_) {
-      _beginToken();
-      next = _tokenizeKeywordOrIdentifier(next, false);
-    }
-    _beginToken();
-    return next;
-  }
-
-  int _tokenizeKeywordOrIdentifier(int next, bool allowDollar) {
-    KeywordState state = KeywordState.KEYWORD_STATE;
-    int start = _reader.offset;
-    while (state != null && $a <= next && next <= $z) {
-      state = state.next(next);
-      next = _reader.advance();
-    }
-    if (state == null || state.keyword() == null) {
-      return _tokenizeIdentifier(next, start, allowDollar);
-    }
-    if (($A <= next && next <= $Z) ||
-        ($0 <= next && next <= $9) ||
-        next == $_ ||
-        next == $$) {
-      return _tokenizeIdentifier(next, start, allowDollar);
-    } else if (next < 128) {
-      _appendKeywordToken(state.keyword());
-      return next;
-    } else {
-      return _tokenizeIdentifier(next, start, allowDollar);
-    }
-  }
-
-  int _tokenizeLessThan(int next) {
-    // < <= << <<=
-    next = _reader.advance();
-    if ($equal == next) {
-      _appendTokenOfType(TokenType.LT_EQ);
-      return _reader.advance();
-    } else if ($lt == next) {
-      return _select($equal, TokenType.LT_LT_EQ, TokenType.LT_LT);
-    } else {
-      _appendTokenOfType(TokenType.LT);
-      return next;
-    }
-  }
-
-  int _tokenizeMinus(int next) {
-    // - -- -=
-    next = _reader.advance();
-    if (next == $minus) {
-      _appendTokenOfType(TokenType.MINUS_MINUS);
-      return _reader.advance();
-    } else if (next == $equal) {
-      _appendTokenOfType(TokenType.MINUS_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.MINUS);
-      return next;
-    }
-  }
-
-  int _tokenizeMultiLineComment(int next) {
-    int nesting = 1;
-    next = _reader.advance();
-    while (true) {
-      if (-1 == next) {
-        _reportError(ScannerErrorCode.UNTERMINATED_MULTI_LINE_COMMENT);
-        _appendCommentToken(
-            TokenType.MULTI_LINE_COMMENT, _reader.getString(_tokenStart, 0));
-        return next;
-      } else if ($asterisk == next) {
-        next = _reader.advance();
-        if ($slash == next) {
-          --nesting;
-          if (0 == nesting) {
-            _appendCommentToken(TokenType.MULTI_LINE_COMMENT,
-                _reader.getString(_tokenStart, 0));
-            return _reader.advance();
-          } else {
-            next = _reader.advance();
-          }
-        }
-      } else if ($slash == next) {
-        next = _reader.advance();
-        if ($asterisk == next) {
-          next = _reader.advance();
-          ++nesting;
-        }
-      } else if (next == $cr) {
-        next = _reader.advance();
-        if (next == $lf) {
-          next = _reader.advance();
-        }
-        recordStartOfLine();
-      } else if (next == $lf) {
-        next = _reader.advance();
-        recordStartOfLine();
-      } else {
-        next = _reader.advance();
-      }
-    }
-  }
-
-  int _tokenizeMultiLineRawString(int quoteChar, int start) {
-    int next = _reader.advance();
-    outer:
-    while (next != -1) {
-      while (next != quoteChar) {
-        if (next == -1) {
-          break outer;
-        } else if (next == $cr) {
-          next = _reader.advance();
-          if (next == $lf) {
-            next = _reader.advance();
-          }
-          recordStartOfLine();
-        } else if (next == $lf) {
-          next = _reader.advance();
-          recordStartOfLine();
-        } else {
-          next = _reader.advance();
-        }
-      }
-      next = _reader.advance();
-      if (next == quoteChar) {
-        next = _reader.advance();
-        if (next == quoteChar) {
-          _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-          return _reader.advance();
-        }
-      }
-    }
-    _reportError(ScannerErrorCode.UNTERMINATED_STRING_LITERAL);
-    _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-    return _reader.advance();
-  }
-
-  int _tokenizeMultiLineString(int quoteChar, int start, bool raw) {
-    if (raw) {
-      return _tokenizeMultiLineRawString(quoteChar, start);
-    }
-    int next = _reader.advance();
-    while (next != -1) {
-      if (next == $$) {
-        _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        next = _tokenizeStringInterpolation(start);
-        _beginToken();
-        start = _reader.offset;
-        continue;
-      }
-      if (next == quoteChar) {
-        next = _reader.advance();
-        if (next == quoteChar) {
-          next = _reader.advance();
-          if (next == quoteChar) {
-            _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-            return _reader.advance();
-          }
-        }
-        continue;
-      }
-      if (next == $backslash) {
-        next = _reader.advance();
-        if (next == -1) {
-          break;
-        }
-        if (next == $cr) {
-          next = _reader.advance();
-          if (next == $lf) {
-            next = _reader.advance();
-          }
-          recordStartOfLine();
-        } else if (next == $lf) {
-          recordStartOfLine();
-          next = _reader.advance();
-        } else {
-          next = _reader.advance();
-        }
-      } else if (next == $cr) {
-        next = _reader.advance();
-        if (next == $lf) {
-          next = _reader.advance();
-        }
-        recordStartOfLine();
-      } else if (next == $lf) {
-        recordStartOfLine();
-        next = _reader.advance();
-      } else {
-        next = _reader.advance();
-      }
-    }
-    _reportError(ScannerErrorCode.UNTERMINATED_STRING_LITERAL);
-    if (start == _reader.offset) {
-      _appendStringTokenWithOffset(TokenType.STRING, "", 1);
-    } else {
-      _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-    }
-    return _reader.advance();
-  }
-
-  int _tokenizeMultiply(int next) =>
-      _select($equal, TokenType.STAR_EQ, TokenType.STAR);
-
-  int _tokenizeNumber(int next) {
-    int start = _reader.offset;
-    while (true) {
-      next = _reader.advance();
-      if ($0 <= next && next <= $9) {
-        continue;
-      } else if (next == $dot) {
-        return _tokenizeFractionPart(_reader.advance(), start);
-      } else if (next == $e || next == $E) {
-        return _tokenizeFractionPart(next, start);
-      } else {
-        _appendStringToken(
-            TokenType.INT, _reader.getString(start, next < 0 ? 0 : -1));
-        return next;
-      }
-    }
-  }
-
-  int _tokenizeOpenSquareBracket(int next) {
-    // [ []  []=
-    next = _reader.advance();
-    if (next == $close_bracket) {
-      return _select($equal, TokenType.INDEX_EQ, TokenType.INDEX);
-    } else {
-      _appendBeginToken(TokenType.OPEN_SQUARE_BRACKET);
-      return next;
-    }
-  }
-
-  int _tokenizePercent(int next) =>
-      _select($equal, TokenType.PERCENT_EQ, TokenType.PERCENT);
-
-  int _tokenizePlus(int next) {
-    // + ++ +=
-    next = _reader.advance();
-    if ($plus == next) {
-      _appendTokenOfType(TokenType.PLUS_PLUS);
-      return _reader.advance();
-    } else if ($equal == next) {
-      _appendTokenOfType(TokenType.PLUS_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.PLUS);
-      return next;
-    }
-  }
-
-  int _tokenizeQuestion() {
-    // ? ?. ?? ??=
-    int next = _reader.advance();
-    if (next == $dot) {
-      // '.'
-      _appendTokenOfType(TokenType.QUESTION_PERIOD);
-      return _reader.advance();
-    } else if (next == $question) {
-      // '?'
-      next = _reader.advance();
-      if (next == $equal) {
-        // '='
-        _appendTokenOfType(TokenType.QUESTION_QUESTION_EQ);
-        return _reader.advance();
-      } else {
-        _appendTokenOfType(TokenType.QUESTION_QUESTION);
-        return next;
-      }
-    } else {
-      _appendTokenOfType(TokenType.QUESTION);
-      return next;
-    }
-  }
-
-  int _tokenizeSingleLineComment(int next) {
-    while (true) {
-      next = _reader.advance();
-      if (-1 == next) {
-        _appendCommentToken(
-            TokenType.SINGLE_LINE_COMMENT, _reader.getString(_tokenStart, 0));
-        return next;
-      } else if ($lf == next || $cr == next) {
-        _appendCommentToken(
-            TokenType.SINGLE_LINE_COMMENT, _reader.getString(_tokenStart, -1));
-        return next;
-      }
-    }
-  }
-
-  int _tokenizeSingleLineRawString(int next, int quoteChar, int start) {
-    next = _reader.advance();
-    while (next != -1) {
-      if (next == quoteChar) {
-        _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-        return _reader.advance();
-      } else if (next == $cr || next == $lf) {
-        _reportError(ScannerErrorCode.UNTERMINATED_STRING_LITERAL);
-        _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        return _reader.advance();
-      }
-      next = _reader.advance();
-    }
-    _reportError(ScannerErrorCode.UNTERMINATED_STRING_LITERAL);
-    _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-    return _reader.advance();
-  }
-
-  int _tokenizeSingleLineString(int next, int quoteChar, int start) {
-    while (next != quoteChar) {
-      if (next == $backslash) {
-        next = _reader.advance();
-      } else if (next == $$) {
-        _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        next = _tokenizeStringInterpolation(start);
-        _beginToken();
-        start = _reader.offset;
-        continue;
-      }
-      if (next <= $cr && (next == $lf || next == $cr || next == -1)) {
-        _reportError(ScannerErrorCode.UNTERMINATED_STRING_LITERAL);
-        if (start == _reader.offset) {
-          _appendStringTokenWithOffset(TokenType.STRING, "", 1);
-        } else if (next == -1) {
-          _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-        } else {
-          _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        }
-        return _reader.advance();
-      }
-      next = _reader.advance();
-    }
-    _appendStringToken(TokenType.STRING, _reader.getString(start, 0));
-    return _reader.advance();
-  }
-
-  int _tokenizeSlashOrComment(int next) {
-    next = _reader.advance();
-    if ($asterisk == next) {
-      return _tokenizeMultiLineComment(next);
-    } else if ($slash == next) {
-      return _tokenizeSingleLineComment(next);
-    } else if ($equal == next) {
-      _appendTokenOfType(TokenType.SLASH_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.SLASH);
-      return next;
-    }
-  }
-
-  int _tokenizeString(int next, int start, bool raw) {
-    int quoteChar = next;
-    next = _reader.advance();
-    if (quoteChar == next) {
-      next = _reader.advance();
-      if (quoteChar == next) {
-        // Multiline string.
-        return _tokenizeMultiLineString(quoteChar, start, raw);
-      } else {
-        // Empty string.
-        _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        return next;
-      }
-    }
-    if (raw) {
-      return _tokenizeSingleLineRawString(next, quoteChar, start);
-    } else {
-      return _tokenizeSingleLineString(next, quoteChar, start);
-    }
-  }
-
-  int _tokenizeStringInterpolation(int start) {
-    _beginToken();
-    int next = _reader.advance();
-    if (next == $lbrace) {
-      return _tokenizeInterpolatedExpression(next, start);
-    } else {
-      return _tokenizeInterpolatedIdentifier(next, start);
-    }
-  }
-
-  int _tokenizeTag(int next) {
-    // # or #!.*[\n\r]
-    if (_reader.offset == 0) {
-      if (_reader.peek() == $exclamation) {
-        do {
-          next = _reader.advance();
-        } while (next != $lf && next != $cr && next > 0);
-        _appendStringToken(
-            TokenType.SCRIPT_TAG, _reader.getString(_tokenStart, 0));
-        return next;
-      }
-    }
-    _appendTokenOfType(TokenType.HASH);
-    return _reader.advance();
-  }
-
-  int _tokenizeTilde(int next) {
-    // ~ ~/ ~/=
-    next = _reader.advance();
-    if (next == $slash) {
-      return _select($equal, TokenType.TILDE_SLASH_EQ, TokenType.TILDE_SLASH);
-    } else {
-      _appendTokenOfType(TokenType.TILDE);
-      return next;
-    }
-  }
-
-  /**
-   * Checks if [value] is a single-line or multi-line comment.
-   */
-  static bool _isDocumentationComment(String value) {
-    return StringUtilities.startsWith3(value, 0, $slash, $slash, $slash) ||
-        StringUtilities.startsWith3(value, 0, $slash, $asterisk, $asterisk);
+  @override
+  void reportError(
+      ScannerErrorCode errorCode, int offset, List<Object> arguments) {
+    _errorListener
+        .onError(new AnalysisError(source, offset, 1, errorCode, arguments));
   }
 }