Roll Observatory packages and add a roll script

analyzer/lib/src/generated/scanner.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;
-
-import 'dart:collection';
-
-import 'error.dart';
-import 'java_engine.dart';
-import 'source.dart';
-
-/**
- * The opening half of a grouping pair of tokens. This is used for curly
- * brackets ('{'), parentheses ('('), and square brackets ('[').
- */
-class BeginToken extends Token {
-  /**
-   * The token that corresponds to this token.
-   */
-  Token endToken;
-
-  /**
-   * Initialize a newly created token to have the given [type] at the given
-   * [offset].
-   */
-  BeginToken(TokenType type, int offset) : super(type, offset) {
-    assert(type == TokenType.OPEN_CURLY_BRACKET ||
-        type == TokenType.OPEN_PAREN ||
-        type == TokenType.OPEN_SQUARE_BRACKET ||
-        type == TokenType.STRING_INTERPOLATION_EXPRESSION);
-  }
-
-  @override
-  Token copy() => new BeginToken(type, offset);
-}
-
-/**
- * A begin token that is preceded by comments.
- */
-class BeginTokenWithComment extends BeginToken {
-  /**
-   * The first comment in the list of comments that precede this token.
-   */
-  CommentToken _precedingComment;
-
-  /**
-   * Initialize a newly created token to have the given [type] at the given
-   * [offset] and to be preceded by the comments reachable from the given
-   * [comment].
-   */
-  BeginTokenWithComment(TokenType type, int offset, this._precedingComment)
-      : super(type, offset) {
-    _setCommentParent(_precedingComment);
-  }
-
-  CommentToken get precedingComments => _precedingComment;
-
-  void set precedingComments(CommentToken comment) {
-    _precedingComment = comment;
-    _setCommentParent(_precedingComment);
-  }
-
-  @override
-  void applyDelta(int delta) {
-    super.applyDelta(delta);
-    Token token = precedingComments;
-    while (token != null) {
-      token.applyDelta(delta);
-      token = token.next;
-    }
-  }
-
-  @override
-  Token copy() =>
-      new BeginTokenWithComment(type, offset, copyComments(precedingComments));
-}
-
-/**
- * A [CharacterReader] that reads a range of characters from another character
- * reader.
- */
-class CharacterRangeReader extends CharacterReader {
-  /**
-   * The reader from which the characters are actually being read.
-   */
-  final CharacterReader baseReader;
-
-  /**
-   * The last character to be read.
-   */
-  final int endIndex;
-
-  /**
-   * Initialize a newly created reader to read the characters from the given
-   * [baseReader] between the [startIndex] inclusive to [endIndex] exclusive.
-   */
-  CharacterRangeReader(this.baseReader, int startIndex, this.endIndex) {
-    baseReader.offset = startIndex - 1;
-  }
-
-  @override
-  int get offset => baseReader.offset;
-
-  @override
-  void set offset(int offset) {
-    baseReader.offset = offset;
-  }
-
-  @override
-  int advance() {
-    if (baseReader.offset + 1 >= endIndex) {
-      return -1;
-    }
-    return baseReader.advance();
-  }
-
-  @override
-  String getString(int start, int endDelta) =>
-      baseReader.getString(start, endDelta);
-
-  @override
-  int peek() {
-    if (baseReader.offset + 1 >= endIndex) {
-      return -1;
-    }
-    return baseReader.peek();
-  }
-}
-
-/**
- * An object used by the scanner to read the characters to be scanned.
- */
-abstract class CharacterReader {
-  /**
-   * The current offset relative to the beginning of the source. Return the
-   * initial offset if the scanner has not yet scanned the source code, and one
-   * (1) past the end of the source code if the entire source code has been
-   * scanned.
-   */
-  int get offset;
-
-  /**
-   * Set the current offset relative to the beginning of the source to the given
-   * [offset]. The new offset must be between the initial offset and one (1)
-   * past the end of the source code.
-   */
-  void set offset(int offset);
-
-  /**
-   * Advance the current position and return the character at the new current
-   * position.
-   */
-  int advance();
-
-  /**
-   * Return the substring of the source code between the [start] offset and the
-   * modified current position. The current position is modified by adding the
-   * [endDelta], which is the number of characters after the current location to
-   * be included in the string, or the number of characters before the current
-   * location to be excluded if the offset is negative.
-   */
-  String getString(int start, int endDelta);
-
-  /**
-   * Return the character at the current position without changing the current
-   * position.
-   */
-  int peek();
-}
-
-/**
- * A [CharacterReader] that reads characters from a character sequence.
- */
-class CharSequenceReader implements CharacterReader {
-  /**
-   * The sequence from which characters will be read.
-   */
-  final String _sequence;
-
-  /**
-   * The number of characters in the string.
-   */
-  int _stringLength = 0;
-
-  /**
-   * The index, relative to the string, of the last character that was read.
-   */
-  int _charOffset = 0;
-
-  /**
-   * Initialize a newly created reader to read the characters in the given
-   * [_sequence].
-   */
-  CharSequenceReader(this._sequence) {
-    this._stringLength = _sequence.length;
-    this._charOffset = -1;
-  }
-
-  @override
-  int get offset => _charOffset;
-
-  @override
-  void set offset(int offset) {
-    _charOffset = offset;
-  }
-
-  @override
-  int advance() {
-    if (_charOffset + 1 >= _stringLength) {
-      return -1;
-    }
-    return _sequence.codeUnitAt(++_charOffset);
-  }
-
-  @override
-  String getString(int start, int endDelta) =>
-      _sequence.substring(start, _charOffset + 1 + endDelta).toString();
-
-  @override
-  int peek() {
-    if (_charOffset + 1 >= _stringLength) {
-      return -1;
-    }
-    return _sequence.codeUnitAt(_charOffset + 1);
-  }
-}
-
-/**
- * A token representing a comment.
- */
-class CommentToken extends StringToken {
-  /**
-   * The [Token] that contains this comment.
-   */
-  Token parent;
-
-  /**
-   * Initialize a newly created token to represent a token of the given [type]
-   * with the given [value] at the given [offset].
-   */
-  CommentToken(TokenType type, String value, int offset)
-      : super(type, value, offset);
-
-  @override
-  CommentToken copy() => new CommentToken(type, _value, offset);
-}
-
-/**
- * A documentation comment token.
- */
-class DocumentationCommentToken extends CommentToken {
-  /**
-   * The references embedded within the documentation comment.
-   * This list will be empty unless this is a documentation comment that has
-   * references embedded within it.
-   */
-  final List<Token> references = <Token>[];
-
-  /**
-   * Initialize a newly created token to represent a token of the given [type]
-   * with the given [value] at the given [offset].
-   */
-  DocumentationCommentToken(TokenType type, String value, int offset)
-      : super(type, value, offset);
-
-  @override
-  CommentToken copy() => new DocumentationCommentToken(type, _value, offset);
-}
-
-/**
- * The keywords in the Dart programming language.
- */
-class Keyword {
-  static const Keyword ASSERT = const Keyword('ASSERT', "assert");
-
-  static const Keyword BREAK = const Keyword('BREAK', "break");
-
-  static const Keyword CASE = const Keyword('CASE', "case");
-
-  static const Keyword CATCH = const Keyword('CATCH', "catch");
-
-  static const Keyword CLASS = const Keyword('CLASS', "class");
-
-  static const Keyword CONST = const Keyword('CONST', "const");
-
-  static const Keyword CONTINUE = const Keyword('CONTINUE', "continue");
-
-  static const Keyword DEFAULT = const Keyword('DEFAULT', "default");
-
-  static const Keyword DO = const Keyword('DO', "do");
-
-  static const Keyword ELSE = const Keyword('ELSE', "else");
-
-  static const Keyword ENUM = const Keyword('ENUM', "enum");
-
-  static const Keyword EXTENDS = const Keyword('EXTENDS', "extends");
-
-  static const Keyword FALSE = const Keyword('FALSE', "false");
-
-  static const Keyword FINAL = const Keyword('FINAL', "final");
-
-  static const Keyword FINALLY = const Keyword('FINALLY', "finally");
-
-  static const Keyword FOR = const Keyword('FOR', "for");
-
-  static const Keyword IF = const Keyword('IF', "if");
-
-  static const Keyword IN = const Keyword('IN', "in");
-
-  static const Keyword IS = const Keyword('IS', "is");
-
-  static const Keyword NEW = const Keyword('NEW', "new");
-
-  static const Keyword NULL = const Keyword('NULL', "null");
-
-  static const Keyword RETHROW = const Keyword('RETHROW', "rethrow");
-
-  static const Keyword RETURN = const Keyword('RETURN', "return");
-
-  static const Keyword SUPER = const Keyword('SUPER', "super");
-
-  static const Keyword SWITCH = const Keyword('SWITCH', "switch");
-
-  static const Keyword THIS = const Keyword('THIS', "this");
-
-  static const Keyword THROW = const Keyword('THROW', "throw");
-
-  static const Keyword TRUE = const Keyword('TRUE', "true");
-
-  static const Keyword TRY = const Keyword('TRY', "try");
-
-  static const Keyword VAR = const Keyword('VAR', "var");
-
-  static const Keyword VOID = const Keyword('VOID', "void");
-
-  static const Keyword WHILE = const Keyword('WHILE', "while");
-
-  static const Keyword WITH = const Keyword('WITH', "with");
-
-  static const Keyword ABSTRACT = const Keyword('ABSTRACT', "abstract", true);
-
-  static const Keyword AS = const Keyword('AS', "as", true);
-
-  static const Keyword DEFERRED = const Keyword('DEFERRED', "deferred", true);
-
-  static const Keyword DYNAMIC = const Keyword('DYNAMIC', "dynamic", true);
-
-  static const Keyword EXPORT = const Keyword('EXPORT', "export", true);
-
-  static const Keyword EXTERNAL = const Keyword('EXTERNAL', "external", true);
-
-  static const Keyword FACTORY = const Keyword('FACTORY', "factory", true);
-
-  static const Keyword GET = const Keyword('GET', "get", true);
-
-  static const Keyword IMPLEMENTS =
-      const Keyword('IMPLEMENTS', "implements", true);
-
-  static const Keyword IMPORT = const Keyword('IMPORT', "import", true);
-
-  static const Keyword LIBRARY = const Keyword('LIBRARY', "library", true);
-
-  static const Keyword OPERATOR = const Keyword('OPERATOR', "operator", true);
-
-  static const Keyword PART = const Keyword('PART', "part", true);
-
-  static const Keyword SET = const Keyword('SET', "set", true);
-
-  static const Keyword STATIC = const Keyword('STATIC', "static", true);
-
-  static const Keyword TYPEDEF = const Keyword('TYPEDEF', "typedef", true);
-
-  static const List<Keyword> values = const [
-    ASSERT,
-    BREAK,
-    CASE,
-    CATCH,
-    CLASS,
-    CONST,
-    CONTINUE,
-    DEFAULT,
-    DO,
-    ELSE,
-    ENUM,
-    EXTENDS,
-    FALSE,
-    FINAL,
-    FINALLY,
-    FOR,
-    IF,
-    IN,
-    IS,
-    NEW,
-    NULL,
-    RETHROW,
-    RETURN,
-    SUPER,
-    SWITCH,
-    THIS,
-    THROW,
-    TRUE,
-    TRY,
-    VAR,
-    VOID,
-    WHILE,
-    WITH,
-    ABSTRACT,
-    AS,
-    DEFERRED,
-    DYNAMIC,
-    EXPORT,
-    EXTERNAL,
-    FACTORY,
-    GET,
-    IMPLEMENTS,
-    IMPORT,
-    LIBRARY,
-    OPERATOR,
-    PART,
-    SET,
-    STATIC,
-    TYPEDEF
-  ];
-
-  /**
-   * A table mapping the lexemes of keywords to the corresponding keyword.
-   */
-  static final Map<String, Keyword> keywords = _createKeywordMap();
-
-  /**
-   * The name of the keyword type.
-   */
-  final String name;
-
-  /**
-   * The lexeme for the keyword.
-   */
-  final String syntax;
-
-  /**
-   * A flag indicating whether the keyword is a pseudo-keyword. Pseudo keywords
-   * can be used as identifiers.
-   */
-  final bool isPseudoKeyword;
-
-  /**
-   * Initialize a newly created keyword to have the given [name] and [syntax].
-   * The keyword is a pseudo-keyword if the [isPseudoKeyword] flag is `true`.
-   */
-  const Keyword(this.name, this.syntax, [this.isPseudoKeyword = false]);
-
-  @override
-  String toString() => name;
-
-  /**
-   * Create a table mapping the lexemes of keywords to the corresponding keyword
-   * and return the table that was created.
-   */
-  static Map<String, Keyword> _createKeywordMap() {
-    LinkedHashMap<String, Keyword> result =
-        new LinkedHashMap<String, Keyword>();
-    for (Keyword keyword in values) {
-      result[keyword.syntax] = keyword;
-    }
-    return result;
-  }
-}
-
-/**
- * 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 - 0x61];
-
-  /**
-   * 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 = 0x0;
-    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 - 0x61] = _computeKeywordStateTable(
-                start + 1, strings, chunkStart, i - chunkStart);
-          }
-          chunkStart = i;
-          chunk = c;
-        }
-      }
-    }
-    if (chunkStart != -1) {
-      assert(result[chunk - 0x61] == null);
-      result[chunk - 0x61] = _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);
-  }
-}
-
-/**
- * A token representing a keyword in the language.
- */
-class KeywordToken extends Token {
-  /**
-   * The keyword being represented by this token.
-   */
-  final Keyword keyword;
-
-  /**
-   * Initialize a newly created token to represent the given [keyword] at the
-   * given [offset].
-   */
-  KeywordToken(this.keyword, int offset) : super(TokenType.KEYWORD, offset);
-
-  @override
-  String get lexeme => keyword.syntax;
-
-  @override
-  Token copy() => new KeywordToken(keyword, offset);
-
-  @override
-  Keyword value() => keyword;
-}
-
-/**
- * A keyword token that is preceded by comments.
- */
-class KeywordTokenWithComment extends KeywordToken {
-  /**
-   * The first comment in the list of comments that precede this token.
-   */
-  CommentToken _precedingComment;
-
-  /**
-   * Initialize a newly created token to to represent the given [keyword] at the
-   * given [offset] and to be preceded by the comments reachable from the given
-   * [comment].
-   */
-  KeywordTokenWithComment(Keyword keyword, int offset, this._precedingComment)
-      : super(keyword, offset) {
-    _setCommentParent(_precedingComment);
-  }
-
-  CommentToken get precedingComments => _precedingComment;
-
-  void set precedingComments(CommentToken comment) {
-    _precedingComment = comment;
-    _setCommentParent(_precedingComment);
-  }
-
-  @override
-  void applyDelta(int delta) {
-    super.applyDelta(delta);
-    Token token = precedingComments;
-    while (token != null) {
-      token.applyDelta(delta);
-      token = token.next;
-    }
-  }
-
-  @override
-  Token copy() => new KeywordTokenWithComment(
-      keyword, offset, copyComments(precedingComments));
-}
-
-/**
- * The class `Scanner` implements a scanner for Dart code.
- *
- * The lexical structure of Dart is ambiguous without knowledge of the context
- * in which a token is being scanned. For example, without context we cannot
- * determine whether source of the form "<<" should be scanned as a single
- * left-shift operator or as two left angle brackets. This scanner does not have
- * any context, so it always resolves such conflicts by scanning the longest
- * possible token.
- */
-class 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;
-
-  /**
-   * Initialize a newly created scanner to scan characters from the given
-   * [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 == 0xD) {
-      // '\r'
-      next = _reader.advance();
-      if (next == 0xA) {
-        // '\n'
-        next = _reader.advance();
-      }
-      recordStartOfLine();
-      return next;
-    } else if (next == 0xA) {
-      // '\n'
-      next = _reader.advance();
-      recordStartOfLine();
-      return next;
-    } else if (next == 0x9 || next == 0x20) {
-      // '\t' || ' '
-      return _reader.advance();
-    }
-    if (next == 0x72) {
-      // 'r'
-      int peek = _reader.peek();
-      if (peek == 0x22 || peek == 0x27) {
-        // '"' || "'"
-        int start = _reader.offset;
-        return _tokenizeString(_reader.advance(), start, true);
-      }
-    }
-    if (0x61 <= next && next <= 0x7A) {
-      // 'a'-'z'
-      return _tokenizeKeywordOrIdentifier(next, true);
-    }
-    if ((0x41 <= next && next <= 0x5A) || next == 0x5F || next == 0x24) {
-      // 'A'-'Z' || '_' || '$'
-      return _tokenizeIdentifier(next, _reader.offset, true);
-    }
-    if (next == 0x3C) {
-      // '<'
-      return _tokenizeLessThan(next);
-    }
-    if (next == 0x3E) {
-      // '>'
-      return _tokenizeGreaterThan(next);
-    }
-    if (next == 0x3D) {
-      // '='
-      return _tokenizeEquals(next);
-    }
-    if (next == 0x21) {
-      // '!'
-      return _tokenizeExclamation(next);
-    }
-    if (next == 0x2B) {
-      // '+'
-      return _tokenizePlus(next);
-    }
-    if (next == 0x2D) {
-      // '-'
-      return _tokenizeMinus(next);
-    }
-    if (next == 0x2A) {
-      // '*'
-      return _tokenizeMultiply(next);
-    }
-    if (next == 0x25) {
-      // '%'
-      return _tokenizePercent(next);
-    }
-    if (next == 0x26) {
-      // '&'
-      return _tokenizeAmpersand(next);
-    }
-    if (next == 0x7C) {
-      // '|'
-      return _tokenizeBar(next);
-    }
-    if (next == 0x5E) {
-      // '^'
-      return _tokenizeCaret(next);
-    }
-    if (next == 0x5B) {
-      // '['
-      return _tokenizeOpenSquareBracket(next);
-    }
-    if (next == 0x7E) {
-      // '~'
-      return _tokenizeTilde(next);
-    }
-    if (next == 0x5C) {
-      // '\\'
-      _appendTokenOfType(TokenType.BACKSLASH);
-      return _reader.advance();
-    }
-    if (next == 0x23) {
-      // '#'
-      return _tokenizeTag(next);
-    }
-    if (next == 0x28) {
-      // '('
-      _appendBeginToken(TokenType.OPEN_PAREN);
-      return _reader.advance();
-    }
-    if (next == 0x29) {
-      // ')'
-      _appendEndToken(TokenType.CLOSE_PAREN, TokenType.OPEN_PAREN);
-      return _reader.advance();
-    }
-    if (next == 0x2C) {
-      // ','
-      _appendTokenOfType(TokenType.COMMA);
-      return _reader.advance();
-    }
-    if (next == 0x3A) {
-      // ':'
-      _appendTokenOfType(TokenType.COLON);
-      return _reader.advance();
-    }
-    if (next == 0x3B) {
-      // ';'
-      _appendTokenOfType(TokenType.SEMICOLON);
-      return _reader.advance();
-    }
-    if (next == 0x3F) {
-      // '?'
-      return _tokenizeQuestion();
-    }
-    if (next == 0x5D) {
-      // ']'
-      _appendEndToken(
-          TokenType.CLOSE_SQUARE_BRACKET, TokenType.OPEN_SQUARE_BRACKET);
-      return _reader.advance();
-    }
-    if (next == 0x60) {
-      // '`'
-      _appendTokenOfType(TokenType.BACKPING);
-      return _reader.advance();
-    }
-    if (next == 0x7B) {
-      // '{'
-      _appendBeginToken(TokenType.OPEN_CURLY_BRACKET);
-      return _reader.advance();
-    }
-    if (next == 0x7D) {
-      // '}'
-      _appendEndToken(
-          TokenType.CLOSE_CURLY_BRACKET, TokenType.OPEN_CURLY_BRACKET);
-      return _reader.advance();
-    }
-    if (next == 0x2F) {
-      // '/'
-      return _tokenizeSlashOrComment(next);
-    }
-    if (next == 0x40) {
-      // '@'
-      _appendTokenOfType(TokenType.AT);
-      return _reader.advance();
-    }
-    if (next == 0x22 || next == 0x27) {
-      // '"' || "'"
-      return _tokenizeString(next, _reader.offset, false);
-    }
-    if (next == 0x2E) {
-      // '.'
-      return _tokenizeDotOrNumber(next);
-    }
-    if (next == 0x30) {
-      // '0'
-      return _tokenizeHexOrNumber(next);
-    }
-    if (0x31 <= next && next <= 0x39) {
-      // '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) {
-    // Ignore comment tokens if client specified that it doesn't need them.
-    if (!_preserveComments) {
-      return;
-    }
-    // OK, remember comment tokens.
-    CommentToken token;
-    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;
-  }
-
-  /**
-   * 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 == 0x26) {
-      _appendTokenOfType(TokenType.AMPERSAND_AMPERSAND);
-      return _reader.advance();
-    } else if (next == 0x3D) {
-      _appendTokenOfType(TokenType.AMPERSAND_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.AMPERSAND);
-      return next;
-    }
-  }
-
-  int _tokenizeBar(int next) {
-    // | || |=
-    next = _reader.advance();
-    if (next == 0x7C) {
-      _appendTokenOfType(TokenType.BAR_BAR);
-      return _reader.advance();
-    } else if (next == 0x3D) {
-      _appendTokenOfType(TokenType.BAR_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.BAR);
-      return next;
-    }
-  }
-
-  int _tokenizeCaret(int next) =>
-      _select(0x3D, TokenType.CARET_EQ, TokenType.CARET);
-
-  int _tokenizeDotOrNumber(int next) {
-    int start = _reader.offset;
-    next = _reader.advance();
-    if (0x30 <= next && next <= 0x39) {
-      return _tokenizeFractionPart(next, start);
-    } else if (0x2E == next) {
-      return _select(
-          0x2E, TokenType.PERIOD_PERIOD_PERIOD, TokenType.PERIOD_PERIOD);
-    } else {
-      _appendTokenOfType(TokenType.PERIOD);
-      return next;
-    }
-  }
-
-  int _tokenizeEquals(int next) {
-    // = == =>
-    next = _reader.advance();
-    if (next == 0x3D) {
-      _appendTokenOfType(TokenType.EQ_EQ);
-      return _reader.advance();
-    } else if (next == 0x3E) {
-      _appendTokenOfType(TokenType.FUNCTION);
-      return _reader.advance();
-    }
-    _appendTokenOfType(TokenType.EQ);
-    return next;
-  }
-
-  int _tokenizeExclamation(int next) {
-    // ! !=
-    next = _reader.advance();
-    if (next == 0x3D) {
-      _appendTokenOfType(TokenType.BANG_EQ);
-      return _reader.advance();
-    }
-    _appendTokenOfType(TokenType.BANG);
-    return next;
-  }
-
-  int _tokenizeExponent(int next) {
-    if (next == 0x2B || next == 0x2D) {
-      next = _reader.advance();
-    }
-    bool hasDigits = false;
-    while (true) {
-      if (0x30 <= next && next <= 0x39) {
-        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 (0x30 <= next && next <= 0x39) {
-        hasDigit = true;
-      } else if (0x65 == next || 0x45 == 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 (0x2E == next) {
-        return _selectWithOffset(0x2E, 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;
-  }
-
-  int _tokenizeGreaterThan(int next) {
-    // > >= >> >>=
-    next = _reader.advance();
-    if (0x3D == next) {
-      _appendTokenOfType(TokenType.GT_EQ);
-      return _reader.advance();
-    } else if (0x3E == next) {
-      next = _reader.advance();
-      if (0x3D == 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 ((0x30 <= next && next <= 0x39) ||
-          (0x41 <= next && next <= 0x46) ||
-          (0x61 <= next && next <= 0x66)) {
-        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 == 0x78 || x == 0x58) {
-      _reader.advance();
-      return _tokenizeHex(x);
-    }
-    return _tokenizeNumber(next);
-  }
-
-  int _tokenizeIdentifier(int next, int start, bool allowDollar) {
-    while ((0x61 <= next && next <= 0x7A) ||
-        (0x41 <= next && next <= 0x5A) ||
-        (0x30 <= next && next <= 0x39) ||
-        next == 0x5F ||
-        (next == 0x24 && 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 == 0x7D) {
-        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 ((0x41 <= next && next <= 0x5A) ||
-        (0x61 <= next && next <= 0x7A) ||
-        next == 0x5F) {
-      _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 && 0x61 <= next && next <= 0x7A) {
-      state = state.next(next);
-      next = _reader.advance();
-    }
-    if (state == null || state.keyword() == null) {
-      return _tokenizeIdentifier(next, start, allowDollar);
-    }
-    if ((0x41 <= next && next <= 0x5A) ||
-        (0x30 <= next && next <= 0x39) ||
-        next == 0x5F ||
-        next == 0x24) {
-      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 (0x3D == next) {
-      _appendTokenOfType(TokenType.LT_EQ);
-      return _reader.advance();
-    } else if (0x3C == next) {
-      return _select(0x3D, TokenType.LT_LT_EQ, TokenType.LT_LT);
-    } else {
-      _appendTokenOfType(TokenType.LT);
-      return next;
-    }
-  }
-
-  int _tokenizeMinus(int next) {
-    // - -- -=
-    next = _reader.advance();
-    if (next == 0x2D) {
-      _appendTokenOfType(TokenType.MINUS_MINUS);
-      return _reader.advance();
-    } else if (next == 0x3D) {
-      _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 (0x2A == next) {
-        next = _reader.advance();
-        if (0x2F == next) {
-          --nesting;
-          if (0 == nesting) {
-            _appendCommentToken(TokenType.MULTI_LINE_COMMENT,
-                _reader.getString(_tokenStart, 0));
-            return _reader.advance();
-          } else {
-            next = _reader.advance();
-          }
-        }
-      } else if (0x2F == next) {
-        next = _reader.advance();
-        if (0x2A == next) {
-          next = _reader.advance();
-          ++nesting;
-        }
-      } else if (next == 0xD) {
-        next = _reader.advance();
-        if (next == 0xA) {
-          next = _reader.advance();
-        }
-        recordStartOfLine();
-      } else if (next == 0xA) {
-        recordStartOfLine();
-        next = _reader.advance();
-      } 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 == 0xD) {
-          next = _reader.advance();
-          if (next == 0xA) {
-            next = _reader.advance();
-          }
-          recordStartOfLine();
-        } else if (next == 0xA) {
-          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 == 0x24) {
-        _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 == 0x5C) {
-        next = _reader.advance();
-        if (next == -1) {
-          break;
-        }
-        if (next == 0xD) {
-          next = _reader.advance();
-          if (next == 0xA) {
-            next = _reader.advance();
-          }
-          recordStartOfLine();
-        } else if (next == 0xA) {
-          recordStartOfLine();
-          next = _reader.advance();
-        } else {
-          next = _reader.advance();
-        }
-      } else if (next == 0xD) {
-        next = _reader.advance();
-        if (next == 0xA) {
-          next = _reader.advance();
-        }
-        recordStartOfLine();
-      } else if (next == 0xA) {
-        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(0x3D, TokenType.STAR_EQ, TokenType.STAR);
-
-  int _tokenizeNumber(int next) {
-    int start = _reader.offset;
-    while (true) {
-      next = _reader.advance();
-      if (0x30 <= next && next <= 0x39) {
-        continue;
-      } else if (next == 0x2E) {
-        return _tokenizeFractionPart(_reader.advance(), start);
-      } else if (next == 0x65 || next == 0x45) {
-        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 == 0x5D) {
-      return _select(0x3D, TokenType.INDEX_EQ, TokenType.INDEX);
-    } else {
-      _appendBeginToken(TokenType.OPEN_SQUARE_BRACKET);
-      return next;
-    }
-  }
-
-  int _tokenizePercent(int next) =>
-      _select(0x3D, TokenType.PERCENT_EQ, TokenType.PERCENT);
-
-  int _tokenizePlus(int next) {
-    // + ++ +=
-    next = _reader.advance();
-    if (0x2B == next) {
-      _appendTokenOfType(TokenType.PLUS_PLUS);
-      return _reader.advance();
-    } else if (0x3D == next) {
-      _appendTokenOfType(TokenType.PLUS_EQ);
-      return _reader.advance();
-    } else {
-      _appendTokenOfType(TokenType.PLUS);
-      return next;
-    }
-  }
-
-  int _tokenizeQuestion() {
-    // ? ?. ?? ??=
-    int next = _reader.advance();
-    if (next == 0x2E) {
-      // '.'
-      _appendTokenOfType(TokenType.QUESTION_PERIOD);
-      return _reader.advance();
-    } else if (next == 0x3F) {
-      // '?'
-      next = _reader.advance();
-      if (next == 0x3D) {
-        // '='
-        _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 (0xA == next || 0xD == 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 == 0xD || next == 0xA) {
-        _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 == 0x5C) {
-        next = _reader.advance();
-      } else if (next == 0x24) {
-        _appendStringToken(TokenType.STRING, _reader.getString(start, -1));
-        next = _tokenizeStringInterpolation(start);
-        _beginToken();
-        start = _reader.offset;
-        continue;
-      }
-      if (next <= 0xD && (next == 0xA || next == 0xD || 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 (0x2A == next) {
-      return _tokenizeMultiLineComment(next);
-    } else if (0x2F == next) {
-      return _tokenizeSingleLineComment(next);
-    } else if (0x3D == 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 == 0x7B) {
-      return _tokenizeInterpolatedExpression(next, start);
-    } else {
-      return _tokenizeInterpolatedIdentifier(next, start);
-    }
-  }
-
-  int _tokenizeTag(int next) {
-    // # or #!.*[\n\r]
-    if (_reader.offset == 0) {
-      if (_reader.peek() == 0x21) {
-        do {
-          next = _reader.advance();
-        } while (next != 0xA && next != 0xD && 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 == 0x2F) {
-      return _select(0x3D, 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, 0x2F, 0x2F, 0x2F) ||
-        StringUtilities.startsWith3(value, 0, 0x2F, 0x2A, 0x2A);
-  }
-}
-
-/**
- * The error codes used for errors detected by the scanner.
- */
-class ScannerErrorCode extends ErrorCode {
-  static const ScannerErrorCode ILLEGAL_CHARACTER =
-      const ScannerErrorCode('ILLEGAL_CHARACTER', "Illegal character {0}");
-
-  static const ScannerErrorCode MISSING_DIGIT =
-      const ScannerErrorCode('MISSING_DIGIT', "Decimal digit expected");
-
-  static const ScannerErrorCode MISSING_HEX_DIGIT =
-      const ScannerErrorCode('MISSING_HEX_DIGIT', "Hexidecimal digit expected");
-
-  static const ScannerErrorCode MISSING_QUOTE =
-      const ScannerErrorCode('MISSING_QUOTE', "Expected quote (' or \")");
-
-  static const ScannerErrorCode UNABLE_GET_CONTENT = const ScannerErrorCode(
-      'UNABLE_GET_CONTENT', "Unable to get content: {0}");
-
-  static const ScannerErrorCode UNTERMINATED_MULTI_LINE_COMMENT =
-      const ScannerErrorCode(
-          'UNTERMINATED_MULTI_LINE_COMMENT', "Unterminated multi-line comment");
-
-  static const ScannerErrorCode UNTERMINATED_STRING_LITERAL =
-      const ScannerErrorCode(
-          'UNTERMINATED_STRING_LITERAL', "Unterminated string literal");
-
-  /**
-   * Initialize a newly created error code to have the given [name]. The message
-   * associated with the error will be created from the given [message]
-   * template. The correction associated with the error will be created from the
-   * given [correction] template.
-   */
-  const ScannerErrorCode(String name, String message, [String correction])
-      : super(name, message, correction);
-
-  @override
-  ErrorSeverity get errorSeverity => ErrorSeverity.ERROR;
-
-  @override
-  ErrorType get type => ErrorType.SYNTACTIC_ERROR;
-}
-
-/**
- * A token whose value is independent of it's type.
- */
-class StringToken extends Token {
-  /**
-   * The lexeme represented by this token.
-   */
-  String _value;
-
-  /**
-   * Initialize a newly created token to represent a token of the given [type]
-   * with the given [value] at the given [offset].
-   */
-  StringToken(TokenType type, String value, int offset) : super(type, offset) {
-    this._value = StringUtilities.intern(value);
-  }
-
-  @override
-  String get lexeme => _value;
-
-  @override
-  Token copy() => new StringToken(type, _value, offset);
-
-  @override
-  String value() => _value;
-}
-
-/**
- * A string token that is preceded by comments.
- */
-class StringTokenWithComment extends StringToken {
-  /**
-   * The first comment in the list of comments that precede this token.
-   */
-  CommentToken _precedingComment;
-
-  /**
-   * Initialize a newly created token to have the given [type] at the given
-   * [offset] and to be preceded by the comments reachable from the given
-   * [comment].
-   */
-  StringTokenWithComment(
-      TokenType type, String value, int offset, this._precedingComment)
-      : super(type, value, offset) {
-    _setCommentParent(_precedingComment);
-  }
-
-  CommentToken get precedingComments => _precedingComment;
-
-  void set precedingComments(CommentToken comment) {
-    _precedingComment = comment;
-    _setCommentParent(_precedingComment);
-  }
-
-  @override
-  void applyDelta(int delta) {
-    super.applyDelta(delta);
-    Token token = precedingComments;
-    while (token != null) {
-      token.applyDelta(delta);
-      token = token.next;
-    }
-  }
-
-  @override
-  Token copy() => new StringTokenWithComment(
-      type, lexeme, offset, copyComments(precedingComments));
-}
-
-/**
- * A [CharacterReader] that reads characters from a character sequence, but adds
- * a delta when reporting the current character offset so that the character
- * sequence can be a subsequence from a larger sequence.
- */
-class SubSequenceReader extends CharSequenceReader {
-  /**
-   * The offset from the beginning of the file to the beginning of the source
-   * being scanned.
-   */
-  final int _offsetDelta;
-
-  /**
-   * Initialize a newly created reader to read the characters in the given
-   * [sequence]. The [_offsetDelta] is the offset from the beginning of the file
-   * to the beginning of the source being scanned
-   */
-  SubSequenceReader(String sequence, this._offsetDelta) : super(sequence);
-
-  @override
-  int get offset => _offsetDelta + super.offset;
-
-  @override
-  void set offset(int offset) {
-    super.offset = offset - _offsetDelta;
-  }
-
-  @override
-  String getString(int start, int endDelta) =>
-      super.getString(start - _offsetDelta, endDelta);
-}
-
-/**
- * A token whose value is independent of it's type.
- */
-class SyntheticStringToken extends StringToken {
-  /**
-   * Initialize a newly created token to represent a token of the given [type]
-   * with the given [value] at the given [offset].
-   */
-  SyntheticStringToken(TokenType type, String value, int offset)
-      : super(type, value, offset);
-
-  @override
-  bool get isSynthetic => true;
-}
-
-/**
- * A token that was scanned from the input. Each token knows which tokens
- * precede and follow it, acting as a link in a doubly linked list of tokens.
- */
-class Token {
-  /**
-   * The type of the token.
-   */
-  final TokenType type;
-
-  /**
-   * The offset from the beginning of the file to the first character in the
-   * token.
-   */
-  int offset = 0;
-
-  /**
-   * The previous token in the token stream.
-   */
-  Token previous;
-
-  /**
-   * The next token in the token stream.
-   */
-  Token _next;
-
-  /**
-   * Initialize a newly created token to have the given [type] and [offset].
-   */
-  Token(this.type, int offset) {
-    this.offset = offset;
-  }
-
-  /**
-   * Return the offset from the beginning of the file to the character after the
-   * last character of the token.
-   */
-  int get end => offset + length;
-
-  /**
-   * Return `true` if this token represents an operator.
-   */
-  bool get isOperator => type.isOperator;
-
-  /**
-   * Return `true` if this token is a synthetic token. A synthetic token is a
-   * token that was introduced by the parser in order to recover from an error
-   * in the code.
-   */
-  bool get isSynthetic => length == 0;
-
-  /**
-   * Return `true` if this token represents an operator that can be defined by
-   * users.
-   */
-  bool get isUserDefinableOperator => type.isUserDefinableOperator;
-
-  /**
-   * Return the number of characters in the node's source range.
-   */
-  int get length => lexeme.length;
-
-  /**
-   * Return the lexeme that represents this token.
-   */
-  String get lexeme => type.lexeme;
-
-  /**
-   * Return the next token in the token stream.
-   */
-  Token get next => _next;
-
-  /**
-   * Return the first comment in the list of comments that precede this token,
-   * or `null` if there are no comments preceding this token. Additional
-   * comments can be reached by following the token stream using [next] until
-   * `null` is returned.
-   *
-   * For example, if the original contents were "/* one */ /* two */ id", then
-   * the first preceding comment token will have a lexeme of "/* one */" and
-   * the next comment token will have a lexeme of "/* two */".
-   */
-  CommentToken get precedingComments => null;
-
-  /**
-   * Apply (add) the given [delta] to this token's offset.
-   */
-  void applyDelta(int delta) {
-    offset += delta;
-  }
-
-  /**
-   * Return a newly created token that is a copy of this token but that is not a
-   * part of any token stream.
-   */
-  Token copy() => new Token(type, offset);
-
-  /**
-   * Copy a linked list of comment tokens identical to the given comment tokens.
-   */
-  Token copyComments(Token token) {
-    if (token == null) {
-      return null;
-    }
-    Token head = token.copy();
-    Token tail = head;
-    token = token.next;
-    while (token != null) {
-      tail = tail.setNext(token.copy());
-      token = token.next;
-    }
-    return head;
-  }
-
-  /**
-   * Return `true` if this token has any one of the given [types].
-   */
-  bool matchesAny(List<TokenType> types) {
-    for (TokenType type in types) {
-      if (this.type == type) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  /**
-   * Set the next token in the token stream to the given [token]. This has the
-   * side-effect of setting this token to be the previous token for the given
-   * token. Return the token that was passed in.
-   */
-  Token setNext(Token token) {
-    _next = token;
-    token.previous = this;
-    return token;
-  }
-
-  /**
-   * Set the next token in the token stream to the given token without changing
-   * which token is the previous token for the given token. Return the token
-   * that was passed in.
-   */
-  Token setNextWithoutSettingPrevious(Token token) {
-    _next = token;
-    return token;
-  }
-
-  @override
-  String toString() => lexeme;
-
-  /**
-   * Return the value of this token. For keyword tokens, this is the keyword
-   * associated with the token, for other tokens it is the lexeme associated
-   * with the token.
-   */
-  Object value() => type.lexeme;
-
-  /**
-   * Sets the `parent` property to `this` for the given [comment] and all the
-   * next tokens.
-   */
-  void _setCommentParent(CommentToken comment) {
-    while (comment != null) {
-      comment.parent = this;
-      comment = comment.next;
-    }
-  }
-
-  /**
-   * Compare the given [tokens] to find the token that appears first in the
-   * source being parsed. That is, return the left-most of all of the tokens.
-   * The list must be non-`null`, but the elements of the list are allowed to be
-   * `null`. Return the token with the smallest offset, or `null` if the list is
-   * empty or if all of the elements of the list are `null`.
-   */
-  static Token lexicallyFirst(List<Token> tokens) {
-    Token first = null;
-    int offset = -1;
-    for (Token token in tokens) {
-      if (token != null && (offset < 0 || token.offset < offset)) {
-        first = token;
-        offset = token.offset;
-      }
-    }
-    return first;
-  }
-}
-
-/**
- * The classes (or groups) of tokens with a similar use.
- */
-class TokenClass {
-  /**
-   * A value used to indicate that the token type is not part of any specific
-   * class of token.
-   */
-  static const TokenClass NO_CLASS = const TokenClass('NO_CLASS');
-
-  /**
-   * A value used to indicate that the token type is an additive operator.
-   */
-  static const TokenClass ADDITIVE_OPERATOR =
-      const TokenClass('ADDITIVE_OPERATOR', 13);
-
-  /**
-   * A value used to indicate that the token type is an assignment operator.
-   */
-  static const TokenClass ASSIGNMENT_OPERATOR =
-      const TokenClass('ASSIGNMENT_OPERATOR', 1);
-
-  /**
-   * A value used to indicate that the token type is a bitwise-and operator.
-   */
-  static const TokenClass BITWISE_AND_OPERATOR =
-      const TokenClass('BITWISE_AND_OPERATOR', 11);
-
-  /**
-   * A value used to indicate that the token type is a bitwise-or operator.
-   */
-  static const TokenClass BITWISE_OR_OPERATOR =
-      const TokenClass('BITWISE_OR_OPERATOR', 9);
-
-  /**
-   * A value used to indicate that the token type is a bitwise-xor operator.
-   */
-  static const TokenClass BITWISE_XOR_OPERATOR =
-      const TokenClass('BITWISE_XOR_OPERATOR', 10);
-
-  /**
-   * A value used to indicate that the token type is a cascade operator.
-   */
-  static const TokenClass CASCADE_OPERATOR =
-      const TokenClass('CASCADE_OPERATOR', 2);
-
-  /**
-   * A value used to indicate that the token type is a conditional operator.
-   */
-  static const TokenClass CONDITIONAL_OPERATOR =
-      const TokenClass('CONDITIONAL_OPERATOR', 3);
-
-  /**
-   * A value used to indicate that the token type is an equality operator.
-   */
-  static const TokenClass EQUALITY_OPERATOR =
-      const TokenClass('EQUALITY_OPERATOR', 7);
-
-  /**
-   * A value used to indicate that the token type is an if-null operator.
-   */
-  static const TokenClass IF_NULL_OPERATOR =
-      const TokenClass('IF_NULL_OPERATOR', 4);
-
-  /**
-   * A value used to indicate that the token type is a logical-and operator.
-   */
-  static const TokenClass LOGICAL_AND_OPERATOR =
-      const TokenClass('LOGICAL_AND_OPERATOR', 6);
-
-  /**
-   * A value used to indicate that the token type is a logical-or operator.
-   */
-  static const TokenClass LOGICAL_OR_OPERATOR =
-      const TokenClass('LOGICAL_OR_OPERATOR', 5);
-
-  /**
-   * A value used to indicate that the token type is a multiplicative operator.
-   */
-  static const TokenClass MULTIPLICATIVE_OPERATOR =
-      const TokenClass('MULTIPLICATIVE_OPERATOR', 14);
-
-  /**
-   * A value used to indicate that the token type is a relational operator.
-   */
-  static const TokenClass RELATIONAL_OPERATOR =
-      const TokenClass('RELATIONAL_OPERATOR', 8);
-
-  /**
-   * A value used to indicate that the token type is a shift operator.
-   */
-  static const TokenClass SHIFT_OPERATOR =
-      const TokenClass('SHIFT_OPERATOR', 12);
-
-  /**
-   * A value used to indicate that the token type is a unary operator.
-   */
-  static const TokenClass UNARY_POSTFIX_OPERATOR =
-      const TokenClass('UNARY_POSTFIX_OPERATOR', 16);
-
-  /**
-   * A value used to indicate that the token type is a unary operator.
-   */
-  static const TokenClass UNARY_PREFIX_OPERATOR =
-      const TokenClass('UNARY_PREFIX_OPERATOR', 15);
-
-  /**
-   * The name of the token class.
-   */
-  final String name;
-
-  /**
-   * The precedence of tokens of this class, or `0` if the such tokens do not
-   * represent an operator.
-   */
-  final int precedence;
-
-  const TokenClass(this.name, [this.precedence = 0]);
-
-  @override
-  String toString() => name;
-}
-
-/**
- * The types of tokens that can be returned by the scanner.
- */
-class TokenType {
-  /**
-   * The type of the token that marks the end of the input.
-   */
-  static const TokenType EOF = const TokenType_EOF('EOF');
-
-  static const TokenType DOUBLE = const TokenType('DOUBLE');
-
-  static const TokenType HEXADECIMAL = const TokenType('HEXADECIMAL');
-
-  static const TokenType IDENTIFIER = const TokenType('IDENTIFIER');
-
-  static const TokenType INT = const TokenType('INT');
-
-  static const TokenType KEYWORD = const TokenType('KEYWORD');
-
-  static const TokenType MULTI_LINE_COMMENT =
-      const TokenType('MULTI_LINE_COMMENT');
-
-  static const TokenType SCRIPT_TAG = const TokenType('SCRIPT_TAG');
-
-  static const TokenType SINGLE_LINE_COMMENT =
-      const TokenType('SINGLE_LINE_COMMENT');
-
-  static const TokenType STRING = const TokenType('STRING');
-
-  static const TokenType AMPERSAND =
-      const TokenType('AMPERSAND', TokenClass.BITWISE_AND_OPERATOR, "&");
-
-  static const TokenType AMPERSAND_AMPERSAND = const TokenType(
-      'AMPERSAND_AMPERSAND', TokenClass.LOGICAL_AND_OPERATOR, "&&");
-
-  static const TokenType AMPERSAND_EQ =
-      const TokenType('AMPERSAND_EQ', TokenClass.ASSIGNMENT_OPERATOR, "&=");
-
-  static const TokenType AT = const TokenType('AT', TokenClass.NO_CLASS, "@");
-
-  static const TokenType BANG =
-      const TokenType('BANG', TokenClass.UNARY_PREFIX_OPERATOR, "!");
-
-  static const TokenType BANG_EQ =
-      const TokenType('BANG_EQ', TokenClass.EQUALITY_OPERATOR, "!=");
-
-  static const TokenType BAR =
-      const TokenType('BAR', TokenClass.BITWISE_OR_OPERATOR, "|");
-
-  static const TokenType BAR_BAR =
-      const TokenType('BAR_BAR', TokenClass.LOGICAL_OR_OPERATOR, "||");
-
-  static const TokenType BAR_EQ =
-      const TokenType('BAR_EQ', TokenClass.ASSIGNMENT_OPERATOR, "|=");
-
-  static const TokenType COLON =
-      const TokenType('COLON', TokenClass.NO_CLASS, ":");
-
-  static const TokenType COMMA =
-      const TokenType('COMMA', TokenClass.NO_CLASS, ",");
-
-  static const TokenType CARET =
-      const TokenType('CARET', TokenClass.BITWISE_XOR_OPERATOR, "^");
-
-  static const TokenType CARET_EQ =
-      const TokenType('CARET_EQ', TokenClass.ASSIGNMENT_OPERATOR, "^=");
-
-  static const TokenType CLOSE_CURLY_BRACKET =
-      const TokenType('CLOSE_CURLY_BRACKET', TokenClass.NO_CLASS, "}");
-
-  static const TokenType CLOSE_PAREN =
-      const TokenType('CLOSE_PAREN', TokenClass.NO_CLASS, ")");
-
-  static const TokenType CLOSE_SQUARE_BRACKET =
-      const TokenType('CLOSE_SQUARE_BRACKET', TokenClass.NO_CLASS, "]");
-
-  static const TokenType EQ =
-      const TokenType('EQ', TokenClass.ASSIGNMENT_OPERATOR, "=");
-
-  static const TokenType EQ_EQ =
-      const TokenType('EQ_EQ', TokenClass.EQUALITY_OPERATOR, "==");
-
-  static const TokenType FUNCTION =
-      const TokenType('FUNCTION', TokenClass.NO_CLASS, "=>");
-
-  static const TokenType GT =
-      const TokenType('GT', TokenClass.RELATIONAL_OPERATOR, ">");
-
-  static const TokenType GT_EQ =
-      const TokenType('GT_EQ', TokenClass.RELATIONAL_OPERATOR, ">=");
-
-  static const TokenType GT_GT =
-      const TokenType('GT_GT', TokenClass.SHIFT_OPERATOR, ">>");
-
-  static const TokenType GT_GT_EQ =
-      const TokenType('GT_GT_EQ', TokenClass.ASSIGNMENT_OPERATOR, ">>=");
-
-  static const TokenType HASH =
-      const TokenType('HASH', TokenClass.NO_CLASS, "#");
-
-  static const TokenType INDEX =
-      const TokenType('INDEX', TokenClass.UNARY_POSTFIX_OPERATOR, "[]");
-
-  static const TokenType INDEX_EQ =
-      const TokenType('INDEX_EQ', TokenClass.UNARY_POSTFIX_OPERATOR, "[]=");
-
-  static const TokenType IS =
-      const TokenType('IS', TokenClass.RELATIONAL_OPERATOR, "is");
-
-  static const TokenType LT =
-      const TokenType('LT', TokenClass.RELATIONAL_OPERATOR, "<");
-
-  static const TokenType LT_EQ =
-      const TokenType('LT_EQ', TokenClass.RELATIONAL_OPERATOR, "<=");
-
-  static const TokenType LT_LT =
-      const TokenType('LT_LT', TokenClass.SHIFT_OPERATOR, "<<");
-
-  static const TokenType LT_LT_EQ =
-      const TokenType('LT_LT_EQ', TokenClass.ASSIGNMENT_OPERATOR, "<<=");
-
-  static const TokenType MINUS =
-      const TokenType('MINUS', TokenClass.ADDITIVE_OPERATOR, "-");
-
-  static const TokenType MINUS_EQ =
-      const TokenType('MINUS_EQ', TokenClass.ASSIGNMENT_OPERATOR, "-=");
-
-  static const TokenType MINUS_MINUS =
-      const TokenType('MINUS_MINUS', TokenClass.UNARY_PREFIX_OPERATOR, "--");
-
-  static const TokenType OPEN_CURLY_BRACKET =
-      const TokenType('OPEN_CURLY_BRACKET', TokenClass.NO_CLASS, "{");
-
-  static const TokenType OPEN_PAREN =
-      const TokenType('OPEN_PAREN', TokenClass.UNARY_POSTFIX_OPERATOR, "(");
-
-  static const TokenType OPEN_SQUARE_BRACKET = const TokenType(
-      'OPEN_SQUARE_BRACKET', TokenClass.UNARY_POSTFIX_OPERATOR, "[");
-
-  static const TokenType PERCENT =
-      const TokenType('PERCENT', TokenClass.MULTIPLICATIVE_OPERATOR, "%");
-
-  static const TokenType PERCENT_EQ =
-      const TokenType('PERCENT_EQ', TokenClass.ASSIGNMENT_OPERATOR, "%=");
-
-  static const TokenType PERIOD =
-      const TokenType('PERIOD', TokenClass.UNARY_POSTFIX_OPERATOR, ".");
-
-  static const TokenType PERIOD_PERIOD =
-      const TokenType('PERIOD_PERIOD', TokenClass.CASCADE_OPERATOR, "..");
-
-  static const TokenType PLUS =
-      const TokenType('PLUS', TokenClass.ADDITIVE_OPERATOR, "+");
-
-  static const TokenType PLUS_EQ =
-      const TokenType('PLUS_EQ', TokenClass.ASSIGNMENT_OPERATOR, "+=");
-
-  static const TokenType PLUS_PLUS =
-      const TokenType('PLUS_PLUS', TokenClass.UNARY_PREFIX_OPERATOR, "++");
-
-  static const TokenType QUESTION =
-      const TokenType('QUESTION', TokenClass.CONDITIONAL_OPERATOR, "?");
-
-  static const TokenType QUESTION_PERIOD = const TokenType(
-      'QUESTION_PERIOD', TokenClass.UNARY_POSTFIX_OPERATOR, '?.');
-
-  static const TokenType QUESTION_QUESTION =
-      const TokenType('QUESTION_QUESTION', TokenClass.IF_NULL_OPERATOR, '??');
-
-  static const TokenType QUESTION_QUESTION_EQ = const TokenType(
-      'QUESTION_QUESTION_EQ', TokenClass.ASSIGNMENT_OPERATOR, '??=');
-
-  static const TokenType SEMICOLON =
-      const TokenType('SEMICOLON', TokenClass.NO_CLASS, ";");
-
-  static const TokenType SLASH =
-      const TokenType('SLASH', TokenClass.MULTIPLICATIVE_OPERATOR, "/");
-
-  static const TokenType SLASH_EQ =
-      const TokenType('SLASH_EQ', TokenClass.ASSIGNMENT_OPERATOR, "/=");
-
-  static const TokenType STAR =
-      const TokenType('STAR', TokenClass.MULTIPLICATIVE_OPERATOR, "*");
-
-  static const TokenType STAR_EQ =
-      const TokenType('STAR_EQ', TokenClass.ASSIGNMENT_OPERATOR, "*=");
-
-  static const TokenType STRING_INTERPOLATION_EXPRESSION = const TokenType(
-      'STRING_INTERPOLATION_EXPRESSION', TokenClass.NO_CLASS, "\${");
-
-  static const TokenType STRING_INTERPOLATION_IDENTIFIER = const TokenType(
-      'STRING_INTERPOLATION_IDENTIFIER', TokenClass.NO_CLASS, "\$");
-
-  static const TokenType TILDE =
-      const TokenType('TILDE', TokenClass.UNARY_PREFIX_OPERATOR, "~");
-
-  static const TokenType TILDE_SLASH =
-      const TokenType('TILDE_SLASH', TokenClass.MULTIPLICATIVE_OPERATOR, "~/");
-
-  static const TokenType TILDE_SLASH_EQ =
-      const TokenType('TILDE_SLASH_EQ', TokenClass.ASSIGNMENT_OPERATOR, "~/=");
-
-  static const TokenType BACKPING =
-      const TokenType('BACKPING', TokenClass.NO_CLASS, "`");
-
-  static const TokenType BACKSLASH =
-      const TokenType('BACKSLASH', TokenClass.NO_CLASS, "\\");
-
-  static const TokenType PERIOD_PERIOD_PERIOD =
-      const TokenType('PERIOD_PERIOD_PERIOD', TokenClass.NO_CLASS, "...");
-
-  /**
-   * The class of the token.
-   */
-  final TokenClass _tokenClass;
-
-  /**
-   * The name of the token type.
-   */
-  final String name;
-
-  /**
-   * The lexeme that defines this type of token, or `null` if there is more than
-   * one possible lexeme for this type of token.
-   */
-  final String lexeme;
-
-  const TokenType(this.name,
-      [this._tokenClass = TokenClass.NO_CLASS, this.lexeme = null]);
-
-  /**
-   * Return `true` if this type of token represents an additive operator.
-   */
-  bool get isAdditiveOperator => _tokenClass == TokenClass.ADDITIVE_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents an assignment operator.
-   */
-  bool get isAssignmentOperator =>
-      _tokenClass == TokenClass.ASSIGNMENT_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents an associative operator. An
-   * associative operator is an operator for which the following equality is
-   * true: `(a * b) * c == a * (b * c)`. In other words, if the result of
-   * applying the operator to multiple operands does not depend on the order in
-   * which those applications occur.
-   *
-   * Note: This method considers the logical-and and logical-or operators to be
-   * associative, even though the order in which the application of those
-   * operators can have an effect because evaluation of the right-hand operand
-   * is conditional.
-   */
-  bool get isAssociativeOperator => this == AMPERSAND ||
-      this == AMPERSAND_AMPERSAND ||
-      this == BAR ||
-      this == BAR_BAR ||
-      this == CARET ||
-      this == PLUS ||
-      this == STAR;
-
-  /**
-   * Return `true` if this type of token represents an equality operator.
-   */
-  bool get isEqualityOperator => _tokenClass == TokenClass.EQUALITY_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents an increment operator.
-   */
-  bool get isIncrementOperator =>
-      identical(lexeme, "++") || identical(lexeme, "--");
-
-  /**
-   * Return `true` if this type of token represents a multiplicative operator.
-   */
-  bool get isMultiplicativeOperator =>
-      _tokenClass == TokenClass.MULTIPLICATIVE_OPERATOR;
-
-  /**
-   * Return `true` if this token type represents an operator.
-   */
-  bool get isOperator => _tokenClass != TokenClass.NO_CLASS &&
-      this != OPEN_PAREN &&
-      this != OPEN_SQUARE_BRACKET &&
-      this != PERIOD;
-
-  /**
-   * Return `true` if this type of token represents a relational operator.
-   */
-  bool get isRelationalOperator =>
-      _tokenClass == TokenClass.RELATIONAL_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents a shift operator.
-   */
-  bool get isShiftOperator => _tokenClass == TokenClass.SHIFT_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents a unary postfix operator.
-   */
-  bool get isUnaryPostfixOperator =>
-      _tokenClass == TokenClass.UNARY_POSTFIX_OPERATOR;
-
-  /**
-   * Return `true` if this type of token represents a unary prefix operator.
-   */
-  bool get isUnaryPrefixOperator =>
-      _tokenClass == TokenClass.UNARY_PREFIX_OPERATOR;
-
-  /**
-   * Return `true` if this token type represents an operator that can be defined
-   * by users.
-   */
-  bool get isUserDefinableOperator => identical(lexeme, "==") ||
-      identical(lexeme, "~") ||
-      identical(lexeme, "[]") ||
-      identical(lexeme, "[]=") ||
-      identical(lexeme, "*") ||
-      identical(lexeme, "/") ||
-      identical(lexeme, "%") ||
-      identical(lexeme, "~/") ||
-      identical(lexeme, "+") ||
-      identical(lexeme, "-") ||
-      identical(lexeme, "<<") ||
-      identical(lexeme, ">>") ||
-      identical(lexeme, ">=") ||
-      identical(lexeme, ">") ||
-      identical(lexeme, "<=") ||
-      identical(lexeme, "<") ||
-      identical(lexeme, "&") ||
-      identical(lexeme, "^") ||
-      identical(lexeme, "|");
-
-  /**
-   * Return the precedence of the token, or `0` if the token does not represent
-   * an operator.
-   */
-  int get precedence => _tokenClass.precedence;
-
-  @override
-  String toString() => name;
-}
-
-class TokenType_EOF extends TokenType {
-  const TokenType_EOF(String name) : super(name, TokenClass.NO_CLASS, "");
-
-  @override
-  String toString() => "-eof-";
-}
-
-/**
- * A normal token that is preceded by comments.
- */
-class TokenWithComment extends Token {
-  /**
-   * The first comment in the list of comments that precede this token.
-   */
-  CommentToken _precedingComment;
-
-  /**
-   * Initialize a newly created token to have the given [type] at the given
-   * [offset] and to be preceded by the comments reachable from the given
-   * [comment].
-   */
-  TokenWithComment(TokenType type, int offset, this._precedingComment)
-      : super(type, offset) {
-    _setCommentParent(_precedingComment);
-  }
-
-  CommentToken get precedingComments => _precedingComment;
-
-  void set precedingComments(CommentToken comment) {
-    _precedingComment = comment;
-    _setCommentParent(_precedingComment);
-  }
-
-  @override
-  Token copy() => new TokenWithComment(type, offset, precedingComments);
-}