Merge preparser Scanner with main JavaScript scanner.

src/prescanner.h

Index: src/prescanner.h
diff --git a/src/prescanner.h b/src/prescanner.h
deleted file mode 100644
index 3648c677c7c8a5d94200e0c0ea17cb83f1cd4969..0000000000000000000000000000000000000000
--- a/src/prescanner.h
+++ /dev/null
@@ -1,1054 +0,0 @@
-// Copyright 2010 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#ifndef V8_PRESCANNER_H_
-#define V8_PRESCANNER_H_
-
-#include "token.h"
-#include "char-predicates-inl.h"
-#include "utils.h"
-#include "scanner-base.h"
-
-namespace v8 {
-namespace preparser {
-
-namespace i = v8::internal;
-
-typedef int uc32;
-
-class PreScannerStackGuard {
- public:
-  explicit PreScannerStackGuard(int max_size)
-      : limit_(StackPoint().at() - max_size) { }
-  bool has_overflowed() {
-    return StackPoint().at() < limit_;
-  }
- private:
-  class StackPoint {
-   public:
-    char* at() { return reinterpret_cast<char*>(this); }
-  };
-  char* limit_;
-};
-
-
-// Scanner for preparsing.
-// InputStream is a source of UC16 characters with limited push-back.
-// LiteralsBuffer is a collector of (UTF-8) characters used to capture literals.
-class Scanner {
- public:
-  enum LiteralType {
-    kLiteralNumber,
-    kLiteralIdentifier,
-    kLiteralString,
-    kLiteralRegExp,
-    kLiteralRegExpFlags
-  };
-
-  class LiteralScope {
-   public:
-    explicit LiteralScope(Scanner* self, LiteralType type);
-    ~LiteralScope();
-    void Complete();
-
-   private:
-    Scanner* scanner_;
-    bool complete_;
-  };
-
-  Scanner();
-
-  void Initialize(i::UTF16Buffer* stream);
-
-  // Returns the next token.
-  i::Token::Value Next();
-
-  // Returns the current token again.
-  i::Token::Value current_token() { return current_.token; }
-
-  // One token look-ahead (past the token returned by Next()).
-  i::Token::Value peek() const { return next_.token; }
-
-  // Returns true if there was a line terminator before the peek'ed token.
-  bool has_line_terminator_before_next() const {
-    return has_line_terminator_before_next_;
-  }
-
-  struct Location {
-    Location(int b, int e) : beg_pos(b), end_pos(e) { }
-    Location() : beg_pos(0), end_pos(0) { }
-    int beg_pos;
-    int end_pos;
-  };
-
-  // Returns the location information for the current token
-  // (the token returned by Next()).
-  Location location() const { return current_.location; }
-  // Returns the location information for the look-ahead token
-  // (the token returned by peek()).
-  Location peek_location() const { return next_.location; }
-
-  // Returns the literal string, if any, for the current token (the
-  // token returned by Next()). The string is 0-terminated and in
-  // UTF-8 format; they may contain 0-characters. Literal strings are
-  // collected for identifiers, strings, and numbers.
-  // These functions only give the correct result if the literal
-  // was scanned between calls to StartLiteral() and TerminateLiteral().
-  const char* literal_string() const {
-    return current_.literal_chars;
-  }
-
-  int literal_length() const {
-    // Excluding terminal '\x00' added by TerminateLiteral().
-    return current_.literal_length - 1;
-  }
-
-  i::Vector<const char> literal() const {
-    return i::Vector<const char>(literal_string(), literal_length());
-  }
-
-  // Returns the literal string for the next token (the token that
-  // would be returned if Next() were called).
-  const char* next_literal_string() const {
-    return next_.literal_chars;
-  }
-
-  // Returns the length of the next token (that would be returned if
-  // Next() were called).
-  int next_literal_length() const {
-    // Excluding terminal '\x00' added by TerminateLiteral().
-    return next_.literal_length - 1;
-  }
-
-  i::Vector<const char> next_literal() const {
-    return i::Vector<const char>(next_literal_string(), next_literal_length());
-  }
-
-  // Scans the input as a regular expression pattern, previous
-  // character(s) must be /(=). Returns true if a pattern is scanned.
-  bool ScanRegExpPattern(bool seen_equal);
-  // Returns true if regexp flags are scanned (always since flags can
-  // be empty).
-  bool ScanRegExpFlags();
-
-  // Seek forward to the given position.  This operation does not
-  // work in general, for instance when there are pushed back
-  // characters, but works for seeking forward until simple delimiter
-  // tokens, which is what it is used for.
-  void SeekForward(int pos);
-
-  bool stack_overflow() { return stack_overflow_; }
-
-  static const int kCharacterLookaheadBufferSize = 1;
-  static const int kNoEndPosition = 1;
-
- private:
-  // The current and look-ahead token.
-  struct TokenDesc {
-    i::Token::Value token;
-    Location location;
-    const char* literal_chars;
-    int literal_length;
-  };
-
-  // Default stack limit is 128K pointers.
-  static const int kMaxStackSize = 128 * 1024 * sizeof(void*);  // NOLINT.
-
-  void Init(unibrow::CharacterStream* stream);
-
-  // Literal buffer support
-  inline void StartLiteral(LiteralType type);
-  inline void AddLiteralChar(uc32 ch);
-  inline void AddLiteralCharAdvance();
-  inline void TerminateLiteral();
-  // Stops scanning of a literal, e.g., due to an encountered error.
-  inline void DropLiteral();
-
-  // Low-level scanning support.
-  void Advance() { c0_ = source_->Advance(); }
-  void PushBack(uc32 ch) {
-    source_->PushBack(ch);
-    c0_ = ch;
-  }
-
-  bool SkipWhiteSpace();
-
-  i::Token::Value SkipSingleLineComment();
-  i::Token::Value SkipMultiLineComment();
-
-  inline i::Token::Value Select(i::Token::Value tok);
-  inline i::Token::Value Select(uc32 next,
-                                i::Token::Value then,
-                                i::Token::Value else_);
-
-  // Scans a single JavaScript token.
-  void Scan();
-
-  void ScanDecimalDigits();
-  i::Token::Value ScanNumber(bool seen_period);
-  i::Token::Value ScanIdentifier();
-  uc32 ScanHexEscape(uc32 c, int length);
-  uc32 ScanOctalEscape(uc32 c, int length);
-  void ScanEscape();
-  i::Token::Value ScanString();
-
-  // Scans a possible HTML comment -- begins with '<!'.
-  i::Token::Value ScanHtmlComment();
-
-  // Return the current source position.
-  int source_pos() {
-    return source_->pos() - kCharacterLookaheadBufferSize;
-  }
-
-  // Decodes a unicode escape-sequence which is part of an identifier.
-  // If the escape sequence cannot be decoded the result is kBadRune.
-  uc32 ScanIdentifierUnicodeEscape();
-
-  PreScannerStackGuard stack_guard_;
-
-  TokenDesc current_;  // desc for current token (as returned by Next())
-  TokenDesc next_;     // desc for next token (one token look-ahead)
-  bool has_line_terminator_before_next_;
-
-  // Source.
-  i::UTF16Buffer* source_;
-
-  // Buffer to hold literal values (identifiers, strings, numerals, regexps and
-  // regexp flags) using '\x00'-terminated UTF-8 encoding.
-  // Handles allocation internally.
-  // Notice that the '\x00' termination is meaningless for strings and regexps
-  // which may contain the zero-character, but can be used as terminator for
-  // identifiers, numerals and regexp flags.Collector
-  i::LiteralCollector literal_buffer_;
-
-  bool stack_overflow_;
-
-  // One Unicode character look-ahead; c0_ < 0 at the end of the input.
-  uc32 c0_;
-};
-
-
-// ----------------------------------------------------------------------------
-// Scanner::LiteralScope
-
-Scanner::LiteralScope::LiteralScope(
-    Scanner* self, LiteralType type)
-    : scanner_(self), complete_(false) {
-  self->StartLiteral(type);
-}
-
-
-Scanner::LiteralScope::~LiteralScope() {
-  if (!complete_) scanner_->DropLiteral();
-}
-
-void Scanner::LiteralScope::Complete() {
-  scanner_->TerminateLiteral();
-  complete_ = true;
-}
-
-
-// ----------------------------------------------------------------------------
-// Scanner.
-Scanner::Scanner()
-    : stack_guard_(kMaxStackSize),
-      has_line_terminator_before_next_(false),
-      source_(NULL),
-      stack_overflow_(false) {}
-
-
-void Scanner::Initialize(i::UTF16Buffer* stream) {
-  source_ = stream;
-
-  // Initialize current_ to not refer to a literal.
-  current_.literal_length = 0;
-  // Reset literal buffer.
-  literal_buffer_.Reset();
-
-  // Set c0_ (one character ahead)
-  ASSERT(kCharacterLookaheadBufferSize == 1);
-  Advance();
-
-  // Skip initial whitespace allowing HTML comment ends just like
-  // after a newline and scan first token.
-  has_line_terminator_before_next_ = true;
-  SkipWhiteSpace();
-  Scan();
-}
-
-
-i::Token::Value Scanner::Next() {
-  // BUG 1215673: Find a thread safe way to set a stack limit in
-  // pre-parse mode. Otherwise, we cannot safely pre-parse from other
-  // threads.
-  current_ = next_;
-  // Check for stack-overflow before returning any tokens.
-  if (stack_guard_.has_overflowed()) {
-    stack_overflow_ = true;
-    next_.token = i::Token::ILLEGAL;
-  } else {
-    has_line_terminator_before_next_ = false;
-    Scan();
-  }
-  return current_.token;
-}
-
-
-void Scanner::StartLiteral(LiteralType type) {
-  // Only record string and literal identifiers when preparsing.
-  // Those are the ones that are recorded as symbols. Numbers and
-  // regexps are not recorded.
-  if (type == kLiteralString || type == kLiteralIdentifier) {
-    literal_buffer_.StartLiteral();
-  }
-}
-
-
-void Scanner::AddLiteralChar(uc32 c) {
-  literal_buffer_.AddChar(c);
-}
-
-
-void Scanner::TerminateLiteral() {
-  i::Vector<const char> chars = literal_buffer_.EndLiteral();
-  next_.literal_chars = chars.start();
-  next_.literal_length = chars.length();
-}
-
-
-void Scanner::DropLiteral() {
-  literal_buffer_.DropLiteral();
-}
-
-
-void Scanner::AddLiteralCharAdvance() {
-  AddLiteralChar(c0_);
-  Advance();
-}
-
-
-static inline bool IsByteOrderMark(uc32 c) {
-  // The Unicode value U+FFFE is guaranteed never to be assigned as a
-  // Unicode character; this implies that in a Unicode context the
-  // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF
-  // character expressed in little-endian byte order (since it could
-  // not be a U+FFFE character expressed in big-endian byte
-  // order). Nevertheless, we check for it to be compatible with
-  // Spidermonkey.
-  return c == 0xFEFF || c == 0xFFFE;
-}
-
-
-bool Scanner::SkipWhiteSpace() {
-  int start_position = source_pos();
-
-  while (true) {
-    // We treat byte-order marks (BOMs) as whitespace for better
-    // compatibility with Spidermonkey and other JavaScript engines.
-    while (i::ScannerConstants::kIsWhiteSpace.get(c0_)
-           || IsByteOrderMark(c0_)) {
-      // IsWhiteSpace() includes line terminators!
-      if (i::ScannerConstants::kIsLineTerminator.get(c0_)) {
-        // Ignore line terminators, but remember them. This is necessary
-        // for automatic semicolon insertion.
-        has_line_terminator_before_next_ = true;
-      }
-      Advance();
-    }
-
-    // If there is an HTML comment end '-->' at the beginning of a
-    // line (with only whitespace in front of it), we treat the rest
-    // of the line as a comment. This is in line with the way
-    // SpiderMonkey handles it.
-    if (c0_ == '-' && has_line_terminator_before_next_) {
-      Advance();
-      if (c0_ == '-') {
-        Advance();
-        if (c0_ == '>') {
-          // Treat the rest of the line as a comment.
-          SkipSingleLineComment();
-          // Continue skipping white space after the comment.
-          continue;
-        }
-        PushBack('-');  // undo Advance()
-      }
-      PushBack('-');  // undo Advance()
-    }
-    // Return whether or not we skipped any characters.
-    return source_pos() != start_position;
-  }
-}
-
-
-i::Token::Value Scanner::SkipSingleLineComment() {
-  Advance();
-
-  // The line terminator at the end of the line is not considered
-  // to be part of the single-line comment; it is recognized
-  // separately by the lexical grammar and becomes part of the
-  // stream of input elements for the syntactic grammar (see
-  // ECMA-262, section 7.4, page 12).
-  while (c0_ >= 0 && !i::ScannerConstants::kIsLineTerminator.get(c0_)) {
-    Advance();
-  }
-
-  return i::Token::WHITESPACE;
-}
-
-
-i::Token::Value Scanner::SkipMultiLineComment() {
-  ASSERT(c0_ == '*');
-  Advance();
-
-  while (c0_ >= 0) {
-    char ch = c0_;
-    Advance();
-    // If we have reached the end of the multi-line comment, we
-    // consume the '/' and insert a whitespace. This way all
-    // multi-line comments are treated as whitespace - even the ones
-    // containing line terminators. This contradicts ECMA-262, section
-    // 7.4, page 12, that says that multi-line comments containing
-    // line terminators should be treated as a line terminator, but it
-    // matches the behaviour of SpiderMonkey and KJS.
-    if (ch == '*' && c0_ == '/') {
-      c0_ = ' ';
-      return i::Token::WHITESPACE;
-    }
-  }
-
-  // Unterminated multi-line comment.
-  return i::Token::ILLEGAL;
-}
-
-
-i::Token::Value Scanner::ScanHtmlComment() {
-  // Check for <!-- comments.
-  ASSERT(c0_ == '!');
-  Advance();
-  if (c0_ == '-') {
-    Advance();
-    if (c0_ == '-') return SkipSingleLineComment();
-    PushBack('-');  // undo Advance()
-  }
-  PushBack('!');  // undo Advance()
-  ASSERT(c0_ == '!');
-  return i::Token::LT;
-}
-
-
-void Scanner::Scan() {
-  next_.literal_length = 0;
-  i::Token::Value token;
-  do {
-    // Remember the position of the next token
-    next_.location.beg_pos = source_pos();
-
-    switch (c0_) {
-      case ' ':
-      case '\t':
-        Advance();
-        token = i::Token::WHITESPACE;
-        break;
-
-      case '\n':
-        Advance();
-        has_line_terminator_before_next_ = true;
-        token = i::Token::WHITESPACE;
-        break;
-
-      case '"': case '\'':
-        token = ScanString();
-        break;
-
-      case '<':
-        // < <= << <<= <!--
-        Advance();
-        if (c0_ == '=') {
-          token = Select(i::Token::LTE);
-        } else if (c0_ == '<') {
-          token = Select('=', i::Token::ASSIGN_SHL, i::Token::SHL);
-        } else if (c0_ == '!') {
-          token = ScanHtmlComment();
-        } else {
-          token = i::Token::LT;
-        }
-        break;
-
-      case '>':
-        // > >= >> >>= >>> >>>=
-        Advance();
-        if (c0_ == '=') {
-          token = Select(i::Token::GTE);
-        } else if (c0_ == '>') {
-          // >> >>= >>> >>>=
-          Advance();
-          if (c0_ == '=') {
-            token = Select(i::Token::ASSIGN_SAR);
-          } else if (c0_ == '>') {
-            token = Select('=', i::Token::ASSIGN_SHR, i::Token::SHR);
-          } else {
-            token = i::Token::SAR;
-          }
-        } else {
-          token = i::Token::GT;
-        }
-        break;
-
-      case '=':
-        // = == ===
-        Advance();
-        if (c0_ == '=') {
-          token = Select('=', i::Token::EQ_STRICT, i::Token::EQ);
-        } else {
-          token = i::Token::ASSIGN;
-        }
-        break;
-
-      case '!':
-        // ! != !==
-        Advance();
-        if (c0_ == '=') {
-          token = Select('=', i::Token::NE_STRICT, i::Token::NE);
-        } else {
-          token = i::Token::NOT;
-        }
-        break;
-
-      case '+':
-        // + ++ +=
-        Advance();
-        if (c0_ == '+') {
-          token = Select(i::Token::INC);
-        } else if (c0_ == '=') {
-          token = Select(i::Token::ASSIGN_ADD);
-        } else {
-          token = i::Token::ADD;
-        }
-        break;
-
-      case '-':
-        // - -- --> -=
-        Advance();
-        if (c0_ == '-') {
-          Advance();
-          if (c0_ == '>' && has_line_terminator_before_next_) {
-            // For compatibility with SpiderMonkey, we skip lines that
-            // start with an HTML comment end '-->'.
-            token = SkipSingleLineComment();
-          } else {
-            token = i::Token::DEC;
-          }
-        } else if (c0_ == '=') {
-          token = Select(i::Token::ASSIGN_SUB);
-        } else {
-          token = i::Token::SUB;
-        }
-        break;
-
-      case '*':
-        // * *=
-        token = Select('=', i::Token::ASSIGN_MUL, i::Token::MUL);
-        break;
-
-      case '%':
-        // % %=
-        token = Select('=', i::Token::ASSIGN_MOD, i::Token::MOD);
-        break;
-
-      case '/':
-        // /  // /* /=
-        Advance();
-        if (c0_ == '/') {
-          token = SkipSingleLineComment();
-        } else if (c0_ == '*') {
-          token = SkipMultiLineComment();
-        } else if (c0_ == '=') {
-          token = Select(i::Token::ASSIGN_DIV);
-        } else {
-          token = i::Token::DIV;
-        }
-        break;
-
-      case '&':
-        // & && &=
-        Advance();
-        if (c0_ == '&') {
-          token = Select(i::Token::AND);
-        } else if (c0_ == '=') {
-          token = Select(i::Token::ASSIGN_BIT_AND);
-        } else {
-          token = i::Token::BIT_AND;
-        }
-        break;
-
-      case '|':
-        // | || |=
-        Advance();
-        if (c0_ == '|') {
-          token = Select(i::Token::OR);
-        } else if (c0_ == '=') {
-          token = Select(i::Token::ASSIGN_BIT_OR);
-        } else {
-          token = i::Token::BIT_OR;
-        }
-        break;
-
-      case '^':
-        // ^ ^=
-        token = Select('=', i::Token::ASSIGN_BIT_XOR, i::Token::BIT_XOR);
-        break;
-
-      case '.':
-        // . Number
-        Advance();
-        if (i::IsDecimalDigit(c0_)) {
-          token = ScanNumber(true);
-        } else {
-          token = i::Token::PERIOD;
-        }
-        break;
-
-      case ':':
-        token = Select(i::Token::COLON);
-        break;
-
-      case ';':
-        token = Select(i::Token::SEMICOLON);
-        break;
-
-      case ',':
-        token = Select(i::Token::COMMA);
-        break;
-
-      case '(':
-        token = Select(i::Token::LPAREN);
-        break;
-
-      case ')':
-        token = Select(i::Token::RPAREN);
-        break;
-
-      case '[':
-        token = Select(i::Token::LBRACK);
-        break;
-
-      case ']':
-        token = Select(i::Token::RBRACK);
-        break;
-
-      case '{':
-        token = Select(i::Token::LBRACE);
-        break;
-
-      case '}':
-        token = Select(i::Token::RBRACE);
-        break;
-
-      case '?':
-        token = Select(i::Token::CONDITIONAL);
-        break;
-
-      case '~':
-        token = Select(i::Token::BIT_NOT);
-        break;
-
-      default:
-        if (i::ScannerConstants::kIsIdentifierStart.get(c0_)) {
-          token = ScanIdentifier();
-        } else if (i::IsDecimalDigit(c0_)) {
-          token = ScanNumber(false);
-        } else if (SkipWhiteSpace()) {
-          token = i::Token::WHITESPACE;
-        } else if (c0_ < 0) {
-          token = i::Token::EOS;
-        } else {
-          token = Select(i::Token::ILLEGAL);
-        }
-        break;
-    }
-
-    // Continue scanning for tokens as long as we're just skipping
-    // whitespace.
-  } while (token == i::Token::WHITESPACE);
-
-  next_.location.end_pos = source_pos();
-  next_.token = token;
-}
-
-
-void Scanner::SeekForward(int pos) {
-  source_->SeekForward(pos - 1);
-  Advance();
-  // This function is only called to seek to the location
-  // of the end of a function (at the "}" token). It doesn't matter
-  // whether there was a line terminator in the part we skip.
-  has_line_terminator_before_next_ = false;
-  Scan();
-}
-
-
-uc32 Scanner::ScanHexEscape(uc32 c, int length) {
-  ASSERT(length <= 4);  // prevent overflow
-
-  uc32 digits[4];
-  uc32 x = 0;
-  for (int i = 0; i < length; i++) {
-    digits[i] = c0_;
-    int d = i::HexValue(c0_);
-    if (d < 0) {
-      // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes
-      // should be illegal, but other JS VMs just return the
-      // non-escaped version of the original character.
-
-      // Push back digits read, except the last one (in c0_).
-      for (int j = i-1; j >= 0; j--) {
-        PushBack(digits[j]);
-      }
-      // Notice: No handling of error - treat it as "\u"->"u".
-      return c;
-    }
-    x = x * 16 + d;
-    Advance();
-  }
-
-  return x;
-}
-
-
-// Octal escapes of the forms '\0xx' and '\xxx' are not a part of
-// ECMA-262. Other JS VMs support them.
-uc32 Scanner::ScanOctalEscape(
-    uc32 c, int length) {
-  uc32 x = c - '0';
-  for (int i = 0; i < length; i++) {
-    int d = c0_ - '0';
-    if (d < 0 || d > 7) break;
-    int nx = x * 8 + d;
-    if (nx >= 256) break;
-    x = nx;
-    Advance();
-  }
-  return x;
-}
-
-
-void Scanner::ScanEscape() {
-  uc32 c = c0_;
-  Advance();
-
-  // Skip escaped newlines.
-  if (i::ScannerConstants::kIsLineTerminator.get(c)) {
-    // Allow CR+LF newlines in multiline string literals.
-    if (i::IsCarriageReturn(c) && i::IsLineFeed(c0_)) Advance();
-    // Allow LF+CR newlines in multiline string literals.
-    if (i::IsLineFeed(c) && i::IsCarriageReturn(c0_)) Advance();
-    return;
-  }
-
-  switch (c) {
-    case '\'':  // fall through
-    case '"' :  // fall through
-    case '\\': break;
-    case 'b' : c = '\b'; break;
-    case 'f' : c = '\f'; break;
-    case 'n' : c = '\n'; break;
-    case 'r' : c = '\r'; break;
-    case 't' : c = '\t'; break;
-    case 'u' : c = ScanHexEscape(c, 4); break;
-    case 'v' : c = '\v'; break;
-    case 'x' : c = ScanHexEscape(c, 2); break;
-    case '0' :  // fall through
-    case '1' :  // fall through
-    case '2' :  // fall through
-    case '3' :  // fall through
-    case '4' :  // fall through
-    case '5' :  // fall through
-    case '6' :  // fall through
-    case '7' : c = ScanOctalEscape(c, 2); break;
-  }
-
-  // According to ECMA-262, 3rd, 7.8.4 (p 18ff) these
-  // should be illegal, but they are commonly handled
-  // as non-escaped characters by JS VMs.
-  AddLiteralChar(c);
-}
-
-
-i::Token::Value Scanner::ScanString() {
-  uc32 quote = c0_;
-  Advance();  // consume quote
-
-  LiteralScope literal(this, kLiteralString);
-  while (c0_ != quote && c0_ >= 0
-         && !i::ScannerConstants::kIsLineTerminator.get(c0_)) {
-    uc32 c = c0_;
-    Advance();
-    if (c == '\\') {
-      if (c0_ < 0) return i::Token::ILLEGAL;
-      ScanEscape();
-    } else {
-      AddLiteralChar(c);
-    }
-  }
-  if (c0_ != quote) return i::Token::ILLEGAL;
-  literal.Complete();
-
-  Advance();  // consume quote
-  return i::Token::STRING;
-}
-
-
-i::Token::Value Scanner::Select(
-    i::Token::Value tok) {
-  Advance();
-  return tok;
-}
-
-
-i::Token::Value Scanner::Select(
-    uc32 next,
-    i::Token::Value then,
-    i::Token::Value else_) {
-  Advance();
-  if (c0_ == next) {
-    Advance();
-    return then;
-  } else {
-    return else_;
-  }
-}
-
-
-// Returns true if any decimal digits were scanned, returns false otherwise.
-void Scanner::ScanDecimalDigits() {
-  while (i::IsDecimalDigit(c0_))
-    AddLiteralCharAdvance();
-}
-
-
-i::Token::Value Scanner::ScanNumber(
-    bool seen_period) {
-  // c0_ is the first digit of the number or the fraction.
-  ASSERT(i::IsDecimalDigit(c0_));
-
-  enum { DECIMAL, HEX, OCTAL } kind = DECIMAL;
-
-  LiteralScope literal(this, kLiteralNumber);
-  if (seen_period) {
-    // we have already seen a decimal point of the float
-    AddLiteralChar('.');
-    ScanDecimalDigits();  // we know we have at least one digit
-
-  } else {
-    // if the first character is '0' we must check for octals and hex
-    if (c0_ == '0') {
-      AddLiteralCharAdvance();
-
-      // either 0, 0exxx, 0Exxx, 0.xxx, an octal number, or a hex number
-      if (c0_ == 'x' || c0_ == 'X') {
-        // hex number
-        kind = HEX;
-        AddLiteralCharAdvance();
-        if (!i::IsHexDigit(c0_)) {
-          // we must have at least one hex digit after 'x'/'X'
-          return i::Token::ILLEGAL;
-        }
-        while (i::IsHexDigit(c0_)) {
-          AddLiteralCharAdvance();
-        }
-      } else if ('0' <= c0_ && c0_ <= '7') {
-        // (possible) octal number
-        kind = OCTAL;
-        while (true) {
-          if (c0_ == '8' || c0_ == '9') {
-            kind = DECIMAL;
-            break;
-          }
-          if (c0_  < '0' || '7'  < c0_) break;
-          AddLiteralCharAdvance();
-        }
-      }
-    }
-
-    // Parse decimal digits and allow trailing fractional part.
-    if (kind == DECIMAL) {
-      ScanDecimalDigits();  // optional
-      if (c0_ == '.') {
-        AddLiteralCharAdvance();
-        ScanDecimalDigits();  // optional
-      }
-    }
-  }
-
-  // scan exponent, if any
-  if (c0_ == 'e' || c0_ == 'E') {
-    ASSERT(kind != HEX);  // 'e'/'E' must be scanned as part of the hex number
-    if (kind == OCTAL) return i::Token::ILLEGAL;
-    // scan exponent
-    AddLiteralCharAdvance();
-    if (c0_ == '+' || c0_ == '-')
-      AddLiteralCharAdvance();
-    if (!i::IsDecimalDigit(c0_)) {
-      // we must have at least one decimal digit after 'e'/'E'
-      return i::Token::ILLEGAL;
-    }
-    ScanDecimalDigits();
-  }
-
-  // The source character immediately following a numeric literal must
-  // not be an identifier start or a decimal digit; see ECMA-262
-  // section 7.8.3, page 17 (note that we read only one decimal digit
-  // if the value is 0).
-  if (i::IsDecimalDigit(c0_)
-      || i::ScannerConstants::kIsIdentifierStart.get(c0_))
-    return i::Token::ILLEGAL;
-
-  literal.Complete();
-
-  return i::Token::NUMBER;
-}
-
-
-uc32 Scanner::ScanIdentifierUnicodeEscape() {
-  Advance();
-  if (c0_ != 'u') return unibrow::Utf8::kBadChar;
-  Advance();
-  uc32 c = ScanHexEscape('u', 4);
-  // We do not allow a unicode escape sequence to start another
-  // unicode escape sequence.
-  if (c == '\\') return unibrow::Utf8::kBadChar;
-  return c;
-}
-
-
-i::Token::Value Scanner::ScanIdentifier() {
-  ASSERT(i::ScannerConstants::kIsIdentifierStart.get(c0_));
-
-  LiteralScope literal(this, kLiteralIdentifier);
-  i::KeywordMatcher keyword_match;
-
-  // Scan identifier start character.
-  if (c0_ == '\\') {
-    uc32 c = ScanIdentifierUnicodeEscape();
-    // Only allow legal identifier start characters.
-    if (!i::ScannerConstants::kIsIdentifierStart.get(c)) {
-      return i::Token::ILLEGAL;
-    }
-    AddLiteralChar(c);
-    keyword_match.Fail();
-  } else {
-    AddLiteralChar(c0_);
-    keyword_match.AddChar(c0_);
-    Advance();
-  }
-
-  // Scan the rest of the identifier characters.
-  while (i::ScannerConstants::kIsIdentifierPart.get(c0_)) {
-    if (c0_ == '\\') {
-      uc32 c = ScanIdentifierUnicodeEscape();
-      // Only allow legal identifier part characters.
-      if (!i::ScannerConstants::kIsIdentifierPart.get(c)) {
-        return i::Token::ILLEGAL;
-      }
-      AddLiteralChar(c);
-      keyword_match.Fail();
-    } else {
-      AddLiteralChar(c0_);
-      keyword_match.AddChar(c0_);
-      Advance();
-    }
-  }
-  literal.Complete();
-
-  return keyword_match.token();
-}
-
-
-bool Scanner::ScanRegExpPattern(bool seen_equal) {
-  // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags
-  bool in_character_class = false;
-
-  // Previous token is either '/' or '/=', in the second case, the
-  // pattern starts at =.
-  next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1);
-  next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0);
-
-  // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5,
-  // the scanner should pass uninterpreted bodies to the RegExp
-  // constructor.
-  LiteralScope literal(this, kLiteralRegExp);
-  if (seen_equal)
-    AddLiteralChar('=');
-
-  while (c0_ != '/' || in_character_class) {
-    if (i::ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) {
-      return false;
-    }
-    if (c0_ == '\\') {  // escaped character
-      AddLiteralCharAdvance();
-      if (i::ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) {
-        return false;
-      }
-      AddLiteralCharAdvance();
-    } else {  // unescaped character
-      if (c0_ == '[') in_character_class = true;
-      if (c0_ == ']') in_character_class = false;
-      AddLiteralCharAdvance();
-    }
-  }
-  Advance();  // consume '/'
-
-  literal.Complete();
-
-  return true;
-}
-
-bool Scanner::ScanRegExpFlags() {
-  // Scan regular expression flags.
-  LiteralScope literal(this, kLiteralRegExpFlags);
-  while (i::ScannerConstants::kIsIdentifierPart.get(c0_)) {
-    if (c0_ == '\\') {
-      uc32 c = ScanIdentifierUnicodeEscape();
-      if (c != static_cast<uc32>(unibrow::Utf8::kBadChar)) {
-        // We allow any escaped character, unlike the restriction on
-        // IdentifierPart when it is used to build an IdentifierName.
-        AddLiteralChar(c);
-        continue;
-      }
-    }
-    AddLiteralCharAdvance();
-  }
-  literal.Complete();
-
-  next_.location.end_pos = source_pos() - 1;
-  return true;
-}
-
-
-} }  // namespace v8::preparser
-
-#endif  // V8_PRESCANNER_H_