Solidity scanner and some unit tests.

The scanner is a modified version of the v8 javascript scanner.

5 files changed, 1370 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 00000000..59aa7836
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,49 @@
+cmake_policy(SET CMP0015 NEW)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DSTATICLIB")
+
+aux_source_directory(. SRC_LIST)
+
+set(EXECUTABLE solidity)
+
+if(ETH_STATIC)
+	add_library(${EXECUTABLE} STATIC ${SRC_LIST})
+else()
+	add_library(${EXECUTABLE} SHARED ${SRC_LIST})
+endif()
+
+file(GLOB HEADERS "*.h") 
+
+include_directories(..)
+
+target_link_libraries(${EXECUTABLE} evmface)
+target_link_libraries(${EXECUTABLE} devcore)
+
+
+if("${TARGET_PLATFORM}" STREQUAL "w64")
+	target_link_libraries(${EXECUTABLE} boost_system-mt-s)
+	target_link_libraries(${EXECUTABLE} boost_thread_win32-mt-s)
+	target_link_libraries(${EXECUTABLE} iphlpapi)
+	target_link_libraries(${EXECUTABLE} ws2_32)
+	target_link_libraries(${EXECUTABLE} mswsock)
+	target_link_libraries(${EXECUTABLE} shlwapi)
+elseif (APPLE)
+	# Latest mavericks boost libraries only come with -mt
+	target_link_libraries(${EXECUTABLE} boost_system-mt)
+	target_link_libraries(${EXECUTABLE} boost_thread-mt)
+	find_package(Threads REQUIRED)
+	target_link_libraries(${EXECUTABLE} ${CMAKE_THREAD_LIBS_INIT})
+elseif (UNIX)
+	target_link_libraries(${EXECUTABLE} ${Boost_SYSTEM_LIBRARY})
+	target_link_libraries(${EXECUTABLE} ${Boost_THREAD_LIBRARY})
+	target_link_libraries(${EXECUTABLE} ${CMAKE_THREAD_LIBS_INIT})
+else ()
+	target_link_libraries(${EXECUTABLE} boost_system)
+	target_link_libraries(${EXECUTABLE} boost_thread)
+	find_package(Threads REQUIRED)
+	target_link_libraries(${EXECUTABLE} ${CMAKE_THREAD_LIBS_INIT})
+endif ()
+
+install( TARGETS ${EXECUTABLE} ARCHIVE DESTINATION lib LIBRARY DESTINATION lib )
+install( FILES ${HEADERS} DESTINATION include/${EXECUTABLE} )
+
diff --git a/Scanner.cpp b/Scanner.cpp
new file mode 100644
index 00000000..101b4a1a
--- /dev/null
+++ b/Scanner.cpp
@@ -0,0 +1,653 @@
+// Copyright 2006-2012, 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.
+//
+// Modifications as part of cpp-ethereum under the following license:
+//
+// cpp-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// cpp-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <libsolidity/Scanner.h>
+
+namespace dev {
+namespace solidity {
+
+namespace {
+    bool IsDecimalDigit(char c) {
+        return '0' <= c && c <= '9';
+    }
+    bool IsHexDigit(char c) {
+        return IsDecimalDigit(c)
+                || ('a' <= c && c <= 'f')
+                || ('A' <= c && c <= 'F');
+    }
+    bool IsLineTerminator(char c) { return c == '\n'; }
+    bool IsWhiteSpace(char c) {
+        return c == ' ' || c == '\n' || c == '\t';
+    }
+    bool IsIdentifierStart(char c) {
+        return c == '_' || c == '$' || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z');
+    }
+    bool IsIdentifierPart(char c) {
+        return IsIdentifierStart(c) || IsDecimalDigit(c);
+    }
+
+    int HexValue(char c) {
+        if (c >= '0' && c <= '9') return c - '0';
+        else if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+        else if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+        else return -1;
+    }
+}
+
+Scanner::Scanner(const CharStream& _source)
+{
+    reset(_source);
+}
+
+void Scanner::reset(const CharStream& _source)
+{
+    m_source = _source;
+
+    // Initialize current_ to not refer to a literal.
+    m_current_token.token = Token::ILLEGAL;
+    m_current_token.literal.clear();
+
+    m_hasLineTerminatorBeforeNext = true;
+    m_hasMultilineCommentBeforeNext = false;
+
+    m_char = m_source.get();
+    skipWhitespace();
+    scanToken();
+}
+
+
+bool Scanner::scanHexNumber(char& scanned_number, int expected_length)
+{
+    BOOST_ASSERT(expected_length <= 4);  // prevent overflow
+
+    char x = 0;
+    for (int i = 0; i < expected_length; i++) {
+        int d = HexValue(m_char);
+        if (d < 0) {
+            rollback(i);
+            return false;
+        }
+        x = x * 16 + d;
+        advance();
+    }
+
+    scanned_number = x;
+    return true;
+}
+
+
+// Ensure that tokens can be stored in a byte.
+BOOST_STATIC_ASSERT(Token::NUM_TOKENS <= 0x100);
+
+Token::Value Scanner::next()
+{
+    m_current_token = m_next_token;
+    m_hasLineTerminatorBeforeNext = false;
+    m_hasMultilineCommentBeforeNext = false;
+    scanToken();
+    return m_current_token.token;
+}
+
+bool Scanner::skipWhitespace()
+{
+    const int start_position = getSourcePos();
+
+    while (true) {
+      if (IsLineTerminator(m_char)) {
+        m_hasLineTerminatorBeforeNext = true;
+      } else if (!IsWhiteSpace(m_char)) {
+        break;
+      }
+      advance();
+    }
+
+    // Return whether or not we skipped any characters.
+    return getSourcePos() != start_position;
+}
+
+
+Token::Value Scanner::skipSingleLineComment()
+{
+  // 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
+  while (advance() && !IsLineTerminator(m_char)) { };
+
+  return Token::WHITESPACE;
+}
+
+Token::Value Scanner::skipMultiLineComment()
+{
+    BOOST_ASSERT(m_char == '*');
+    advance();
+
+    while (!isSourcePastEndOfInput()) {
+        char ch = m_char;
+        advance();
+        if (IsLineTerminator(ch)) {
+            // Following ECMA-262, section 7.4, a comment containing
+            // a newline will make the comment count as a line-terminator.
+            m_hasMultilineCommentBeforeNext = true;
+        }
+        // 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.
+        if (ch == '*' && m_char == '/') {
+            m_char = ' ';
+            return Token::WHITESPACE;
+        }
+    }
+
+    // Unterminated multi-line comment.
+    return Token::ILLEGAL;
+}
+
+void Scanner::scanToken()
+{
+  m_next_token.literal.clear();
+  Token::Value token;
+  do {
+    // Remember the position of the next token
+    m_next_token.location.beg_pos = getSourcePos();
+
+    switch (m_char) {
+      case '\n':
+        m_hasLineTerminatorBeforeNext = true; // fall-through
+      case ' ':
+      case '\t':
+        token = selectToken(Token::WHITESPACE);
+        break;
+
+      case '"': case '\'':
+        token = scanString();
+        break;
+
+      case '<':
+        // < <= << <<=
+        advance();
+        if (m_char == '=') {
+          token = selectToken(Token::LTE);
+        } else if (m_char == '<') {
+          token = selectToken('=', Token::ASSIGN_SHL, Token::SHL);
+        } else {
+          token = Token::LT;
+        }
+        break;
+
+      case '>':
+        // > >= >> >>= >>> >>>=
+        advance();
+        if (m_char == '=') {
+          token = selectToken(Token::GTE);
+        } else if (m_char == '>') {
+          // >> >>= >>> >>>=
+          advance();
+          if (m_char == '=') {
+            token = selectToken(Token::ASSIGN_SAR);
+          } else if (m_char == '>') {
+            token = selectToken('=', Token::ASSIGN_SHR, Token::SHR);
+          } else {
+            token = Token::SAR;
+          }
+        } else {
+          token = Token::GT;
+        }
+        break;
+
+      case '=':
+        // = == =>
+        advance();
+        if (m_char == '=') {
+          token = selectToken(Token::EQ);
+        } else if (m_char == '>') {
+          token = selectToken(Token::ARROW);
+        } else {
+          token = Token::ASSIGN;
+        }
+        break;
+
+      case '!':
+        // ! != !==
+        advance();
+        if (m_char == '=') {
+          token = selectToken(Token::NE);
+        } else {
+          token = Token::NOT;
+        }
+        break;
+
+      case '+':
+        // + ++ +=
+        advance();
+        if (m_char == '+') {
+          token = selectToken(Token::INC);
+        } else if (m_char == '=') {
+          token = selectToken(Token::ASSIGN_ADD);
+        } else {
+          token = Token::ADD;
+        }
+        break;
+
+      case '-':
+        // - -- -=
+        advance();
+        if (m_char == '-') {
+          advance();
+          token = Token::DEC;
+        } else if (m_char == '=') {
+          token = selectToken(Token::ASSIGN_SUB);
+        } else {
+          token = Token::SUB;
+        }
+        break;
+
+      case '*':
+        // * *=
+        token = selectToken('=', Token::ASSIGN_MUL, Token::MUL);
+        break;
+
+      case '%':
+        // % %=
+        token = selectToken('=', Token::ASSIGN_MOD, Token::MOD);
+        break;
+
+      case '/':
+        // /  // /* /=
+        advance();
+        if (m_char == '/') {
+          token = skipSingleLineComment();
+        } else if (m_char == '*') {
+          token = skipMultiLineComment();
+        } else if (m_char == '=') {
+          token = selectToken(Token::ASSIGN_DIV);
+        } else {
+          token = Token::DIV;
+        }
+        break;
+
+      case '&':
+        // & && &=
+        advance();
+        if (m_char == '&') {
+          token = selectToken(Token::AND);
+        } else if (m_char == '=') {
+          token = selectToken(Token::ASSIGN_BIT_AND);
+        } else {
+          token = Token::BIT_AND;
+        }
+        break;
+
+      case '|':
+        // | || |=
+        advance();
+        if (m_char == '|') {
+          token = selectToken(Token::OR);
+        } else if (m_char == '=') {
+          token = selectToken(Token::ASSIGN_BIT_OR);
+        } else {
+          token = Token::BIT_OR;
+        }
+        break;
+
+      case '^':
+        // ^ ^=
+        token = selectToken('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR);
+        break;
+
+      case '.':
+        // . Number
+        advance();
+        if (IsDecimalDigit(m_char)) {
+          token = scanNumber(true);
+        } else {
+          token = Token::PERIOD;
+        }
+        break;
+
+      case ':':
+        token = selectToken(Token::COLON);
+        break;
+
+      case ';':
+        token = selectToken(Token::SEMICOLON);
+        break;
+
+      case ',':
+        token = selectToken(Token::COMMA);
+        break;
+
+      case '(':
+        token = selectToken(Token::LPAREN);
+        break;
+
+      case ')':
+        token = selectToken(Token::RPAREN);
+        break;
+
+      case '[':
+        token = selectToken(Token::LBRACK);
+        break;
+
+      case ']':
+        token = selectToken(Token::RBRACK);
+        break;
+
+      case '{':
+        token = selectToken(Token::LBRACE);
+        break;
+
+      case '}':
+        token = selectToken(Token::RBRACE);
+        break;
+
+      case '?':
+        token = selectToken(Token::CONDITIONAL);
+        break;
+
+      case '~':
+        token = selectToken(Token::BIT_NOT);
+        break;
+
+      default:
+        if (IsIdentifierStart(m_char)) {
+          token = scanIdentifierOrKeyword();
+        } else if (IsDecimalDigit(m_char)) {
+          token = scanNumber(false);
+        } else if (skipWhitespace()) {
+          token = Token::WHITESPACE;
+        } else if (isSourcePastEndOfInput()) {
+          token = Token::EOS;
+        } else {
+          token = selectToken(Token::ILLEGAL);
+        }
+        break;
+    }
+
+    // Continue scanning for tokens as long as we're just skipping
+    // whitespace.
+  } while (token == Token::WHITESPACE);
+
+  m_next_token.location.end_pos = getSourcePos();
+  m_next_token.token = token;
+}
+
+bool Scanner::scanEscape()
+{
+    char c = m_char;
+    advance();
+
+    // Skip escaped newlines.
+    if (IsLineTerminator(c))
+        return true;
+
+    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' : {
+        if (!scanHexNumber(c, 4)) return false;
+        break;
+    }
+    case 'v' : c = '\v'; break;
+    case 'x' : {
+        if (!scanHexNumber(c, 2)) return false;
+        break;
+    }
+    }
+
+    // According to ECMA-262, section 7.8.4, characters not covered by the
+    // above cases should be illegal, but they are commonly handled as
+    // non-escaped characters by JS VMs.
+    addLiteralChar(c);
+    return true;
+}
+
+Token::Value Scanner::scanString()
+{
+    const char quote = m_char;
+    advance();  // consume quote
+
+    LiteralScope literal(this);
+    while (m_char != quote && !isSourcePastEndOfInput() && !IsLineTerminator(m_char)) {
+        char c = m_char;
+        advance();
+        if (c == '\\') {
+            if (isSourcePastEndOfInput() || !scanEscape()) return Token::ILLEGAL;
+        } else {
+            addLiteralChar(c);
+        }
+    }
+    if (m_char != quote) return Token::ILLEGAL;
+    literal.Complete();
+
+    advance();  // consume quote
+    return Token::STRING;
+}
+
+
+void Scanner::scanDecimalDigits()
+{
+    while (IsDecimalDigit(m_char))
+        addLiteralCharAndAdvance();
+}
+
+
+Token::Value Scanner::scanNumber(bool _periodSeen)
+{
+  BOOST_ASSERT(IsDecimalDigit(m_char));  // the first digit of the number or the fraction
+
+  enum { DECIMAL, HEX, OCTAL, IMPLICIT_OCTAL, BINARY } kind = DECIMAL;
+
+  LiteralScope literal(this);
+  if (_periodSeen) {
+    // 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 (m_char == '0') {
+      addLiteralCharAndAdvance();
+
+      // either 0, 0exxx, 0Exxx, 0.xxx, a hex number, a binary number or
+      // an octal number.
+      if (m_char == 'x' || m_char == 'X') {
+        // hex number
+        kind = HEX;
+        addLiteralCharAndAdvance();
+        if (!IsHexDigit(m_char)) {
+          // we must have at least one hex digit after 'x'/'X'
+          return Token::ILLEGAL;
+        }
+        while (IsHexDigit(m_char)) {
+          addLiteralCharAndAdvance();
+        }
+      }
+    }
+
+    // Parse decimal digits and allow trailing fractional part.
+    if (kind == DECIMAL) {
+      scanDecimalDigits();  // optional
+      if (m_char == '.') {
+        addLiteralCharAndAdvance();
+        scanDecimalDigits();  // optional
+      }
+    }
+  }
+
+  // scan exponent, if any
+  if (m_char == 'e' || m_char == 'E') {
+    BOOST_ASSERT(kind != HEX);  // 'e'/'E' must be scanned as part of the hex number
+    if (kind != DECIMAL) return Token::ILLEGAL;
+    // scan exponent
+    addLiteralCharAndAdvance();
+    if (m_char == '+' || m_char == '-')
+      addLiteralCharAndAdvance();
+    if (!IsDecimalDigit(m_char)) {
+      // we must have at least one decimal digit after 'e'/'E'
+      return 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 (IsDecimalDigit(m_char) || IsIdentifierStart(m_char))
+    return Token::ILLEGAL;
+
+  literal.Complete();
+
+  return Token::NUMBER;
+}
+
+
+// ----------------------------------------------------------------------------
+// Keyword Matcher
+
+#define KEYWORDS(KEYWORD_GROUP, KEYWORD)                                     \
+  KEYWORD_GROUP('b')                                                         \
+  KEYWORD("break", Token::BREAK)                                             \
+  KEYWORD_GROUP('c')                                                         \
+  KEYWORD("case", Token::CASE)                                               \
+  KEYWORD("catch", Token::CATCH)                                             \
+  KEYWORD("const", Token::CONST)                                             \
+  KEYWORD("continue", Token::CONTINUE)                                       \
+  KEYWORD_GROUP('d')                                                         \
+  KEYWORD("debugger", Token::DEBUGGER)                                       \
+  KEYWORD("default", Token::DEFAULT)                                         \
+  KEYWORD("delete", Token::DELETE)                                           \
+  KEYWORD("do", Token::DO)                                                   \
+  KEYWORD_GROUP('e')                                                         \
+  KEYWORD("else", Token::ELSE)                                               \
+  KEYWORD("enum", Token::FUTURE_RESERVED_WORD)                               \
+  KEYWORD_GROUP('f')                                                         \
+  KEYWORD("false", Token::FALSE_LITERAL)                                     \
+  KEYWORD("finally", Token::FINALLY)                                         \
+  KEYWORD("for", Token::FOR)                                                 \
+  KEYWORD("function", Token::FUNCTION)                                       \
+  KEYWORD_GROUP('i')                                                         \
+  KEYWORD("if", Token::IF)                                                   \
+  KEYWORD("implements", Token::FUTURE_STRICT_RESERVED_WORD)                  \
+  KEYWORD("in", Token::IN)                                                   \
+  KEYWORD("instanceof", Token::INSTANCEOF)                                   \
+  KEYWORD("interface", Token::FUTURE_STRICT_RESERVED_WORD)                   \
+  KEYWORD_GROUP('l')                                                         \
+  KEYWORD_GROUP('n')                                                         \
+  KEYWORD("new", Token::NEW)                                                 \
+  KEYWORD("null", Token::NULL_LITERAL)                                       \
+  KEYWORD_GROUP('p')                                                         \
+  KEYWORD("package", Token::FUTURE_STRICT_RESERVED_WORD)                     \
+  KEYWORD("private", Token::FUTURE_STRICT_RESERVED_WORD)                     \
+  KEYWORD("protected", Token::FUTURE_STRICT_RESERVED_WORD)                   \
+  KEYWORD("public", Token::FUTURE_STRICT_RESERVED_WORD)                      \
+  KEYWORD_GROUP('r')                                                         \
+  KEYWORD("return", Token::RETURN)                                           \
+  KEYWORD_GROUP('s')                                                         \
+  KEYWORD("switch", Token::SWITCH)                                           \
+  KEYWORD_GROUP('t')                                                         \
+  KEYWORD("this", Token::THIS)                                               \
+  KEYWORD("throw", Token::THROW)                                             \
+  KEYWORD("true", Token::TRUE_LITERAL)                                       \
+  KEYWORD("try", Token::TRY)                                                 \
+  KEYWORD("typeof", Token::TYPEOF)                                           \
+  KEYWORD_GROUP('v')                                                         \
+  KEYWORD("var", Token::VAR)                                                 \
+  KEYWORD("void", Token::VOID)                                               \
+  KEYWORD_GROUP('w')                                                         \
+  KEYWORD("while", Token::WHILE)                                             \
+  KEYWORD("with", Token::WITH)
+
+
+static Token::Value KeywordOrIdentifierToken(const std::string& input)
+{
+  BOOST_ASSERT(!input.empty());
+  const int kMinLength = 2;
+  const int kMaxLength = 10;
+  if (input.size() < kMinLength || input.size() > kMaxLength) {
+    return Token::IDENTIFIER;
+  }
+  switch (input[0]) {
+    default:
+#define KEYWORD_GROUP_CASE(ch)                                \
+      break;                                                  \
+    case ch:
+#define KEYWORD(keyword, token)                               \
+    {                                                         \
+      /* 'keyword' is a char array, so sizeof(keyword) is */  \
+      /* strlen(keyword) plus 1 for the NUL char. */          \
+      const int keyword_length = sizeof(keyword) - 1;         \
+      BOOST_STATIC_ASSERT(keyword_length >= kMinLength);      \
+      BOOST_STATIC_ASSERT(keyword_length <= kMaxLength);      \
+      if (input == keyword) {                                 \
+        return token;                                         \
+      }                                                       \
+    }
+    KEYWORDS(KEYWORD_GROUP_CASE, KEYWORD)
+  }
+  return Token::IDENTIFIER;
+}
+
+Token::Value Scanner::scanIdentifierOrKeyword()
+{
+    BOOST_ASSERT(IsIdentifierStart(m_char));
+    LiteralScope literal(this);
+
+    addLiteralCharAndAdvance();
+
+    // Scan the rest of the identifier characters.
+    while (IsIdentifierPart(m_char))
+        addLiteralCharAndAdvance();
+
+    literal.Complete();
+
+    return KeywordOrIdentifierToken(m_next_token.literal);
+}
+
+
+} }
diff --git a/Scanner.h b/Scanner.h
new file mode 100644
index 00000000..3cf52fbc
--- /dev/null
+++ b/Scanner.h
@@ -0,0 +1,252 @@
+// Copyright 2006-2012, 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.
+//
+// Modifications as part of cpp-ethereum under the following license:
+//
+// cpp-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// cpp-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include <boost/assert.hpp>
+
+#include <libdevcore/Common.h>
+#include <libdevcore/Log.h>
+#include <libdevcore/CommonData.h>
+#include <libsolidity/Token.h>
+
+namespace dev {
+namespace solidity {
+
+
+class AstRawString;
+class AstValueFactory;
+class ParserRecorder;
+
+class CharStream {
+public:
+    CharStream()
+        : m_pos(0)
+    {}
+
+    explicit CharStream(const std::string& _source)
+        : m_source(_source), m_pos(0)
+    {}
+    int getPos() const { return m_pos; }
+    bool isPastEndOfInput() const { return m_pos >= m_source.size(); }
+    char get() const { return m_source[m_pos]; }
+    char advanceAndGet() {
+        if (isPastEndOfInput()) return 0;
+        ++m_pos;
+        if (isPastEndOfInput()) return 0;
+        return get();
+    }
+    char rollback(size_t _amount) {
+        BOOST_ASSERT(m_pos >= _amount);
+        m_pos -= _amount;
+        return get();
+    }
+
+private:
+    std::string m_source;
+    size_t m_pos;
+};
+
+// ----------------------------------------------------------------------------
+// JavaScript Scanner.
+
+class Scanner {
+public:
+    // Scoped helper for literal recording. Automatically drops the literal
+    // if aborting the scanning before it's complete.
+    class LiteralScope {
+    public:
+        explicit LiteralScope(Scanner* self)
+            : scanner_(self), complete_(false) {
+            scanner_->startNewLiteral();
+        }
+        ~LiteralScope() {
+            if (!complete_) scanner_->dropLiteral();
+        }
+        void Complete() {
+            complete_ = true;
+        }
+
+    private:
+        Scanner* scanner_;
+        bool complete_;
+    };
+
+    // Representation of an interval of source positions.
+    struct Location {
+        Location(int b, int e) : beg_pos(b), end_pos(e) { }
+        Location() : beg_pos(0), end_pos(0) { }
+
+        bool IsValid() const {
+            return beg_pos >= 0 && end_pos >= beg_pos;
+        }
+
+        static Location invalid() { return Location(-1, -1); }
+
+        int beg_pos;
+        int end_pos;
+    };
+
+    explicit Scanner(const CharStream& _source);
+
+    // Resets the scanner as if newly constructed with _input as input.
+    void reset(const CharStream& _source);
+
+    // Returns the next token and advances input.
+    Token::Value next();
+    // Returns the current token again.
+    Token::Value getCurrentToken() { return m_current_token.token; }
+    // Returns the location information for the current token
+    // (the token last returned by Next()).
+    Location getCurrentLocation() const { return m_current_token.location; }
+    const std::string& getCurrentLiteral() const { return m_current_token.literal; }
+
+    // Similar functions for the upcoming token.
+
+    // One token look-ahead (past the token returned by Next()).
+    Token::Value peek() const { return m_next_token.token; }
+
+    Location peekLocation() const { return m_next_token.location; }
+    const std::string& peekLiteral() const { return m_next_token.literal; }
+
+    // Returns true if there was a line terminator before the peek'ed token,
+    // possibly inside a multi-line comment.
+    bool hasAnyLineTerminatorBeforeNext() const {
+        return m_hasLineTerminatorBeforeNext ||
+                m_hasMultilineCommentBeforeNext;
+    }
+
+private:
+    // Used for the current and look-ahead token.
+    struct TokenDesc {
+        Token::Value token;
+        Location location;
+        std::string literal;
+    };
+
+    static const int kCharacterLookaheadBufferSize = 1;
+
+    // Literal buffer support
+    inline void startNewLiteral() {
+        m_next_token.literal.clear();
+    }
+
+    inline void addLiteralChar(char c) {
+        m_next_token.literal.push_back(c);
+    }
+
+    inline void dropLiteral() {
+        m_next_token.literal.clear();
+    }
+
+    inline void addLiteralCharAndAdvance() {
+        addLiteralChar(m_char);
+        advance();
+    }
+
+    // Low-level scanning support.
+    bool advance() { m_char = m_source.advanceAndGet(); return !m_source.isPastEndOfInput(); }
+    void rollback(int amount) {
+        m_char = m_source.rollback(amount);
+    }
+
+    inline Token::Value selectToken(Token::Value tok) {
+        advance();
+        return tok;
+    }
+
+    inline Token::Value selectToken(char next, Token::Value then, Token::Value else_) {
+        advance();
+        if (m_char == next) {
+            advance();
+            return then;
+        } else {
+            return else_;
+        }
+    }
+
+    bool scanHexNumber(char& scanned_number, int expected_length);
+
+    // Scans a single JavaScript token.
+    void scanToken();
+
+    bool skipWhitespace();
+    Token::Value skipSingleLineComment();
+    Token::Value skipMultiLineComment();
+
+    void scanDecimalDigits();
+    Token::Value scanNumber(bool _periodSeen);
+    Token::Value scanIdentifierOrKeyword();
+
+    Token::Value scanString();
+
+    // Scans an escape-sequence which is part of a string and adds the
+    // decoded character to the current literal. Returns true if a pattern
+    // is scanned.
+    bool scanEscape();
+
+    // Return the current source position.
+    int getSourcePos() {
+        return m_source.getPos();
+    }
+    bool isSourcePastEndOfInput() {
+        return m_source.isPastEndOfInput();
+    }
+
+    TokenDesc m_current_token;  // desc for current token (as returned by Next())
+    TokenDesc m_next_token;     // desc for next token (one token look-ahead)
+
+    CharStream m_source;
+
+    // one character look-ahead, equals 0 at end of input
+    char m_char;
+
+    // Whether there is a line terminator whitespace character after
+    // the current token, and  before the next. Does not count newlines
+    // inside multiline comments.
+    bool m_hasLineTerminatorBeforeNext;
+    // Whether there is a multi-line comment that contains a
+    // line-terminator after the current token, and before the next.
+    bool m_hasMultilineCommentBeforeNext;
+};
+
+} }
diff --git a/Token.cpp b/Token.cpp
new file mode 100644
index 00000000..6ae6456a
--- /dev/null
+++ b/Token.cpp
@@ -0,0 +1,77 @@
+// Copyright 2006-2012, 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.
+//
+// Modifications as part of cpp-ethereum under the following license:
+//
+// cpp-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// cpp-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <libsolidity/Token.h>
+
+namespace dev {
+namespace solidity {
+
+#define T(name, string, precedence) #name,
+const char* const Token::m_name[NUM_TOKENS] = {
+  TOKEN_LIST(T, T)
+};
+#undef T
+
+
+#define T(name, string, precedence) string,
+const char* const Token::m_string[NUM_TOKENS] = {
+  TOKEN_LIST(T, T)
+};
+#undef T
+
+
+#define T(name, string, precedence) precedence,
+const int8_t Token::m_precedence[NUM_TOKENS] = {
+  TOKEN_LIST(T, T)
+};
+#undef T
+
+
+#define KT(a, b, c) 'T',
+#define KK(a, b, c) 'K',
+const char Token::m_tokenType[] = {
+  TOKEN_LIST(KT, KK)
+};
+#undef KT
+#undef KK
+
+} }
diff --git a/Token.h b/Token.h
new file mode 100644
index 00000000..4f5ec194
--- /dev/null
+++ b/Token.h
@@ -0,0 +1,339 @@
+// Copyright 2006-2012, 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.
+//
+// Modifications as part of cpp-ethereum under the following license:
+//
+// cpp-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// cpp-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include <boost/assert.hpp>
+
+#include <libdevcore/Common.h>
+#include <libdevcore/Log.h>
+
+namespace dev {
+namespace solidity {
+
+// TOKEN_LIST takes a list of 3 macros M, all of which satisfy the
+// same signature M(name, string, precedence), where name is the
+// symbolic token name, string is the corresponding syntactic symbol
+// (or NULL, for literals), and precedence is the precedence (or 0).
+// The parameters are invoked for token categories as follows:
+//
+//   T: Non-keyword tokens
+//   K: Keyword tokens
+
+// IGNORE_TOKEN is a convenience macro that can be supplied as
+// an argument (at any position) for a TOKEN_LIST call. It does
+// nothing with tokens belonging to the respective category.
+
+#define IGNORE_TOKEN(name, string, precedence)
+
+#define TOKEN_LIST(T, K)                                             \
+  /* End of source indicator. */                                     \
+  T(EOS, "EOS", 0)                                                   \
+                                                                     \
+  /* Punctuators (ECMA-262, section 7.7, page 15). */                \
+  T(LPAREN, "(", 0)                                                  \
+  T(RPAREN, ")", 0)                                                  \
+  T(LBRACK, "[", 0)                                                  \
+  T(RBRACK, "]", 0)                                                  \
+  T(LBRACE, "{", 0)                                                  \
+  T(RBRACE, "}", 0)                                                  \
+  T(COLON, ":", 0)                                                   \
+  T(SEMICOLON, ";", 0)                                               \
+  T(PERIOD, ".", 0)                                                  \
+  T(CONDITIONAL, "?", 3)                                             \
+  T(INC, "++", 0)                                                    \
+  T(DEC, "--", 0)                                                    \
+  T(ARROW, "=>", 0)                                                  \
+                                                                     \
+  /* Assignment operators. */                                        \
+  /* IsAssignmentOp() and Assignment::is_compound() relies on */     \
+  /* this block of enum values being contiguous and sorted in the */ \
+  /* same order! */                                                  \
+  T(INIT_VAR, "=init_var", 2)                   /* AST-use only. */  \
+  T(INIT_LET, "=init_let", 2)                   /* AST-use only. */  \
+  T(INIT_CONST, "=init_const", 2)               /* AST-use only. */  \
+  T(INIT_CONST_LEGACY, "=init_const_legacy", 2) /* AST-use only. */  \
+  T(ASSIGN, "=", 2)                                                  \
+  T(ASSIGN_BIT_OR, "|=", 2)                                          \
+  T(ASSIGN_BIT_XOR, "^=", 2)                                         \
+  T(ASSIGN_BIT_AND, "&=", 2)                                         \
+  T(ASSIGN_SHL, "<<=", 2)                                            \
+  T(ASSIGN_SAR, ">>=", 2)                                            \
+  T(ASSIGN_SHR, ">>>=", 2)                                           \
+  T(ASSIGN_ADD, "+=", 2)                                             \
+  T(ASSIGN_SUB, "-=", 2)                                             \
+  T(ASSIGN_MUL, "*=", 2)                                             \
+  T(ASSIGN_DIV, "/=", 2)                                             \
+  T(ASSIGN_MOD, "%=", 2)                                             \
+                                                                     \
+  /* Binary operators sorted by precedence. */                       \
+  /* IsBinaryOp() relies on this block of enum values */             \
+  /* being contiguous and sorted in the same order! */               \
+  T(COMMA, ",", 1)                                                   \
+  T(OR, "||", 4)                                                     \
+  T(AND, "&&", 5)                                                    \
+  T(BIT_OR, "|", 6)                                                  \
+  T(BIT_XOR, "^", 7)                                                 \
+  T(BIT_AND, "&", 8)                                                 \
+  T(SHL, "<<", 11)                                                   \
+  T(SAR, ">>", 11)                                                   \
+  T(SHR, ">>>", 11)                                                  \
+  T(ROR, "rotate right", 11) /* only used by Crankshaft */           \
+  T(ADD, "+", 12)                                                    \
+  T(SUB, "-", 12)                                                    \
+  T(MUL, "*", 13)                                                    \
+  T(DIV, "/", 13)                                                    \
+  T(MOD, "%", 13)                                                    \
+                                                                     \
+  /* Compare operators sorted by precedence. */                      \
+  /* IsCompareOp() relies on this block of enum values */            \
+  /* being contiguous and sorted in the same order! */               \
+  T(EQ, "==", 9)                                                     \
+  T(NE, "!=", 9)                                                     \
+  T(EQ_STRICT, "===", 9)                                             \
+  T(NE_STRICT, "!==", 9)                                             \
+  T(LT, "<", 10)                                                     \
+  T(GT, ">", 10)                                                     \
+  T(LTE, "<=", 10)                                                   \
+  T(GTE, ">=", 10)                                                   \
+  K(INSTANCEOF, "instanceof", 10)                                    \
+  K(IN, "in", 10)                                                    \
+                                                                     \
+  /* Unary operators. */                                             \
+  /* IsUnaryOp() relies on this block of enum values */              \
+  /* being contiguous and sorted in the same order! */               \
+  T(NOT, "!", 0)                                                     \
+  T(BIT_NOT, "~", 0)                                                 \
+  K(DELETE, "delete", 0)                                             \
+  K(TYPEOF, "typeof", 0)                                             \
+  K(VOID, "void", 0)                                                 \
+                                                                     \
+  /* Keywords (ECMA-262, section 7.5.2, page 13). */                 \
+  K(BREAK, "break", 0)                                               \
+  K(CASE, "case", 0)                                                 \
+  K(CATCH, "catch", 0)                                               \
+  K(CONTINUE, "continue", 0)                                         \
+  K(DEBUGGER, "debugger", 0)                                         \
+  K(DEFAULT, "default", 0)                                           \
+  /* DELETE */                                                       \
+  K(DO, "do", 0)                                                     \
+  K(ELSE, "else", 0)                                                 \
+  K(FINALLY, "finally", 0)                                           \
+  K(FOR, "for", 0)                                                   \
+  K(FUNCTION, "function", 0)                                         \
+  K(IF, "if", 0)                                                     \
+  /* IN */                                                           \
+  /* INSTANCEOF */                                                   \
+  K(NEW, "new", 0)                                                   \
+  K(RETURN, "return", 0)                                             \
+  K(SWITCH, "switch", 0)                                             \
+  K(THIS, "this", 0)                                                 \
+  K(THROW, "throw", 0)                                               \
+  K(TRY, "try", 0)                                                   \
+  /* TYPEOF */                                                       \
+  K(VAR, "var", 0)                                                   \
+  /* VOID */                                                         \
+  K(WHILE, "while", 0)                                               \
+  K(WITH, "with", 0)                                                 \
+                                                                     \
+  /* Literals (ECMA-262, section 7.8, page 16). */                   \
+  K(NULL_LITERAL, "null", 0)                                         \
+  K(TRUE_LITERAL, "true", 0)                                         \
+  K(FALSE_LITERAL, "false", 0)                                       \
+  T(NUMBER, NULL, 0)                                                 \
+  T(STRING, NULL, 0)                                                 \
+                                                                     \
+  /* Identifiers (not keywords or future reserved words). */         \
+  T(IDENTIFIER, NULL, 0)                                             \
+                                                                     \
+  /* Future reserved words (ECMA-262, section 7.6.1.2). */           \
+  T(FUTURE_RESERVED_WORD, NULL, 0)                                   \
+  T(FUTURE_STRICT_RESERVED_WORD, NULL, 0)                            \
+  K(CLASS, "class", 0)                                               \
+  K(CONST, "const", 0)                                               \
+  K(EXPORT, "export", 0)                                             \
+  K(EXTENDS, "extends", 0)                                           \
+  K(IMPORT, "import", 0)                                             \
+  K(LET, "let", 0)                                                   \
+  K(STATIC, "static", 0)                                             \
+/*  K(YIELD, "yield", 0) */                                              \
+  K(SUPER, "super", 0)                                               \
+                                                                     \
+  /* Illegal token - not able to scan. */                            \
+  T(ILLEGAL, "ILLEGAL", 0)                                           \
+                                                                     \
+  /* Scanner-internal use only. */                                   \
+  T(WHITESPACE, NULL, 0)
+
+
+class Token {
+ public:
+  // All token values.
+#define T(name, string, precedence) name,
+  enum Value {
+    TOKEN_LIST(T, T)
+    NUM_TOKENS
+  };
+#undef T
+
+  // Returns a string corresponding to the C++ token name
+  // (e.g. "LT" for the token LT).
+  static const char* Name(Value tok) {
+    BOOST_ASSERT(tok < NUM_TOKENS);  // tok is unsigned
+    return m_name[tok];
+  }
+
+  // Predicates
+  static bool IsKeyword(Value tok) {
+    return m_tokenType[tok] == 'K';
+  }
+
+  static bool IsIdentifier(Value tok) {
+      return tok == IDENTIFIER;
+  }
+
+  static bool IsAssignmentOp(Value tok) {
+    return INIT_VAR <= tok && tok <= ASSIGN_MOD;
+  }
+
+  static bool IsBinaryOp(Value op) {
+    return COMMA <= op && op <= MOD;
+  }
+
+  static bool IsTruncatingBinaryOp(Value op) {
+    return BIT_OR <= op && op <= ROR;
+  }
+
+  static bool IsCompareOp(Value op) {
+    return EQ <= op && op <= IN;
+  }
+
+  static bool IsOrderedRelationalCompareOp(Value op) {
+    return op == LT || op == LTE || op == GT || op == GTE;
+  }
+
+  static bool IsEqualityOp(Value op) {
+    return op == EQ || op == EQ_STRICT;
+  }
+
+  static bool IsInequalityOp(Value op) {
+    return op == NE || op == NE_STRICT;
+  }
+
+  static bool IsArithmeticCompareOp(Value op) {
+    return IsOrderedRelationalCompareOp(op) ||
+        IsEqualityOp(op) || IsInequalityOp(op);
+  }
+
+  static Value NegateCompareOp(Value op) {
+    BOOST_ASSERT(IsArithmeticCompareOp(op));
+    switch (op) {
+      case EQ: return NE;
+      case NE: return EQ;
+      case EQ_STRICT: return NE_STRICT;
+      case NE_STRICT: return EQ_STRICT;
+      case LT: return GTE;
+      case GT: return LTE;
+      case LTE: return GT;
+      case GTE: return LT;
+      default:
+        BOOST_ASSERT(false); // should not get here
+        return op;
+    }
+  }
+
+  static Value ReverseCompareOp(Value op) {
+    BOOST_ASSERT(IsArithmeticCompareOp(op));
+    switch (op) {
+      case EQ: return EQ;
+      case NE: return NE;
+      case EQ_STRICT: return EQ_STRICT;
+      case NE_STRICT: return NE_STRICT;
+      case LT: return GT;
+      case GT: return LT;
+      case LTE: return GTE;
+      case GTE: return LTE;
+      default:
+        BOOST_ASSERT(false); // should not get here
+        return op;
+    }
+  }
+
+  static bool IsBitOp(Value op) {
+    return (BIT_OR <= op && op <= SHR) || op == BIT_NOT;
+  }
+
+  static bool IsUnaryOp(Value op) {
+    return (NOT <= op && op <= VOID) || op == ADD || op == SUB;
+  }
+
+  static bool IsCountOp(Value op) {
+    return op == INC || op == DEC;
+  }
+
+  static bool IsShiftOp(Value op) {
+    return (SHL <= op) && (op <= SHR);
+  }
+
+  // Returns a string corresponding to the JS token string
+  // (.e., "<" for the token LT) or NULL if the token doesn't
+  // have a (unique) string (e.g. an IDENTIFIER).
+  static const char* String(Value tok) {
+    BOOST_ASSERT(tok < NUM_TOKENS);  // tok is unsigned.
+    return m_string[tok];
+  }
+
+  // Returns the precedence > 0 for binary and compare
+  // operators; returns 0 otherwise.
+  static int Precedence(Value tok) {
+    BOOST_ASSERT(tok < NUM_TOKENS);  // tok is unsigned.
+    return m_precedence[tok];
+  }
+
+ private:
+  static const char* const m_name[NUM_TOKENS];
+  static const char* const m_string[NUM_TOKENS];
+  static const int8_t m_precedence[NUM_TOKENS];
+  static const char m_tokenType[NUM_TOKENS];
+};
+
+} }