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linguist/samples/C++/scanner.cc
Joshua Peek 7b6caa0f6c Rename samples subdirectories
2012-07-23 15:52:49 -05:00

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// Copyright 2011 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.
// Features shared by parsing and pre-parsing scanners.
#include "scanner.h"
#include "../include/v8stdint.h"
#include "char-predicates-inl.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// Scanner
Scanner::Scanner(UnicodeCache* unicode_cache)
: unicode_cache_(unicode_cache),
octal_pos_(Location::invalid()),
harmony_scoping_(false),
harmony_modules_(false) { }
void Scanner::Initialize(Utf16CharacterStream* source) {
source_ = source;
// Need to capture identifiers in order to recognize "get" and "set"
// in object literals.
Init();
// Skip initial whitespace allowing HTML comment ends just like
// after a newline and scan first token.
has_line_terminator_before_next_ = true;
SkipWhiteSpace();
Scan();
}
uc32 Scanner::ScanHexNumber(int expected_length) {
ASSERT(expected_length <= 4); // prevent overflow
uc32 digits[4] = { 0, 0, 0, 0 };
uc32 x = 0;
for (int i = 0; i < expected_length; i++) {
digits[i] = c0_;
int d = 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 that we have advanced past.
for (int j = i-1; j >= 0; j--) {
PushBack(digits[j]);
}
return -1;
}
x = x * 16 + d;
Advance();
}
return x;
}
// Ensure that tokens can be stored in a byte.
STATIC_ASSERT(Token::NUM_TOKENS <= 0x100);
// Table of one-character tokens, by character (0x00..0x7f only).
static const byte one_char_tokens[] = {
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::LPAREN, // 0x28
Token::RPAREN, // 0x29
Token::ILLEGAL,
Token::ILLEGAL,
Token::COMMA, // 0x2c
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::COLON, // 0x3a
Token::SEMICOLON, // 0x3b
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::CONDITIONAL, // 0x3f
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::LBRACK, // 0x5b
Token::ILLEGAL,
Token::RBRACK, // 0x5d
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::ILLEGAL,
Token::LBRACE, // 0x7b
Token::ILLEGAL,
Token::RBRACE, // 0x7d
Token::BIT_NOT, // 0x7e
Token::ILLEGAL
};
Token::Value Scanner::Next() {
current_ = next_;
has_line_terminator_before_next_ = false;
has_multiline_comment_before_next_ = false;
if (static_cast<unsigned>(c0_) <= 0x7f) {
Token::Value token = static_cast<Token::Value>(one_char_tokens[c0_]);
if (token != Token::ILLEGAL) {
int pos = source_pos();
next_.token = token;
next_.location.beg_pos = pos;
next_.location.end_pos = pos + 1;
Advance();
return current_.token;
}
}
Scan();
return current_.token;
}
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 (unicode_cache_->IsWhiteSpace(c0_) || IsByteOrderMark(c0_)) {
// IsWhiteSpace() includes line terminators!
if (unicode_cache_->IsLineTerminator(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;
}
}
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).
while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) {
Advance();
}
return Token::WHITESPACE;
}
Token::Value Scanner::SkipMultiLineComment() {
ASSERT(c0_ == '*');
Advance();
while (c0_ >= 0) {
uc32 ch = c0_;
Advance();
if (unicode_cache_->IsLineTerminator(ch)) {
// Following ECMA-262, section 7.4, a comment containing
// a newline will make the comment count as a line-terminator.
has_multiline_comment_before_next_ = 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 == '*' && c0_ == '/') {
c0_ = ' ';
return Token::WHITESPACE;
}
}
// Unterminated multi-line comment.
return Token::ILLEGAL;
}
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 Token::LT;
}
void Scanner::Scan() {
next_.literal_chars = NULL;
Token::Value token;
do {
// Remember the position of the next token
next_.location.beg_pos = source_pos();
switch (c0_) {
case ' ':
case '\t':
Advance();
token = Token::WHITESPACE;
break;
case '\n':
Advance();
has_line_terminator_before_next_ = true;
token = Token::WHITESPACE;
break;
case '"': case '\'':
token = ScanString();
break;
case '<':
// < <= << <<= <!--
Advance();
if (c0_ == '=') {
token = Select(Token::LTE);
} else if (c0_ == '<') {
token = Select('=', Token::ASSIGN_SHL, Token::SHL);
} else if (c0_ == '!') {
token = ScanHtmlComment();
} else {
token = Token::LT;
}
break;
case '>':
// > >= >> >>= >>> >>>=
Advance();
if (c0_ == '=') {
token = Select(Token::GTE);
} else if (c0_ == '>') {
// >> >>= >>> >>>=
Advance();
if (c0_ == '=') {
token = Select(Token::ASSIGN_SAR);
} else if (c0_ == '>') {
token = Select('=', Token::ASSIGN_SHR, Token::SHR);
} else {
token = Token::SAR;
}
} else {
token = Token::GT;
}
break;
case '=':
// = == ===
Advance();
if (c0_ == '=') {
token = Select('=', Token::EQ_STRICT, Token::EQ);
} else {
token = Token::ASSIGN;
}
break;
case '!':
// ! != !==
Advance();
if (c0_ == '=') {
token = Select('=', Token::NE_STRICT, Token::NE);
} else {
token = Token::NOT;
}
break;
case '+':
// + ++ +=
Advance();
if (c0_ == '+') {
token = Select(Token::INC);
} else if (c0_ == '=') {
token = Select(Token::ASSIGN_ADD);
} else {
token = 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 = Token::DEC;
}
} else if (c0_ == '=') {
token = Select(Token::ASSIGN_SUB);
} else {
token = Token::SUB;
}
break;
case '*':
// * *=
token = Select('=', Token::ASSIGN_MUL, Token::MUL);
break;
case '%':
// % %=
token = Select('=', Token::ASSIGN_MOD, Token::MOD);
break;
case '/':
// / // /* /=
Advance();
if (c0_ == '/') {
token = SkipSingleLineComment();
} else if (c0_ == '*') {
token = SkipMultiLineComment();
} else if (c0_ == '=') {
token = Select(Token::ASSIGN_DIV);
} else {
token = Token::DIV;
}
break;
case '&':
// & && &=
Advance();
if (c0_ == '&') {
token = Select(Token::AND);
} else if (c0_ == '=') {
token = Select(Token::ASSIGN_BIT_AND);
} else {
token = Token::BIT_AND;
}
break;
case '|':
// | || |=
Advance();
if (c0_ == '|') {
token = Select(Token::OR);
} else if (c0_ == '=') {
token = Select(Token::ASSIGN_BIT_OR);
} else {
token = Token::BIT_OR;
}
break;
case '^':
// ^ ^=
token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR);
break;
case '.':
// . Number
Advance();
if (IsDecimalDigit(c0_)) {
token = ScanNumber(true);
} else {
token = Token::PERIOD;
}
break;
case ':':
token = Select(Token::COLON);
break;
case ';':
token = Select(Token::SEMICOLON);
break;
case ',':
token = Select(Token::COMMA);
break;
case '(':
token = Select(Token::LPAREN);
break;
case ')':
token = Select(Token::RPAREN);
break;
case '[':
token = Select(Token::LBRACK);
break;
case ']':
token = Select(Token::RBRACK);
break;
case '{':
token = Select(Token::LBRACE);
break;
case '}':
token = Select(Token::RBRACE);
break;
case '?':
token = Select(Token::CONDITIONAL);
break;
case '~':
token = Select(Token::BIT_NOT);
break;
default:
if (unicode_cache_->IsIdentifierStart(c0_)) {
token = ScanIdentifierOrKeyword();
} else if (IsDecimalDigit(c0_)) {
token = ScanNumber(false);
} else if (SkipWhiteSpace()) {
token = Token::WHITESPACE;
} else if (c0_ < 0) {
token = Token::EOS;
} else {
token = Select(Token::ILLEGAL);
}
break;
}
// Continue scanning for tokens as long as we're just skipping
// whitespace.
} while (token == Token::WHITESPACE);
next_.location.end_pos = source_pos();
next_.token = token;
}
void Scanner::SeekForward(int pos) {
// After this call, we will have the token at the given position as
// the "next" token. The "current" token will be invalid.
if (pos == next_.location.beg_pos) return;
int current_pos = source_pos();
ASSERT_EQ(next_.location.end_pos, current_pos);
// Positions inside the lookahead token aren't supported.
ASSERT(pos >= current_pos);
if (pos != current_pos) {
source_->SeekForward(pos - source_->pos());
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;
has_multiline_comment_before_next_ = false;
}
Scan();
}
bool Scanner::ScanEscape() {
uc32 c = c0_;
Advance();
// Skip escaped newlines.
if (unicode_cache_->IsLineTerminator(c)) {
// Allow CR+LF newlines in multiline string literals.
if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance();
// Allow LF+CR newlines in multiline string literals.
if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance();
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' : {
c = ScanHexNumber(4);
if (c < 0) return false;
break;
}
case 'v' : c = '\v'; break;
case 'x' : {
c = ScanHexNumber(2);
if (c < 0) return false;
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, 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;
}
// 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';
int i = 0;
for (; 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();
}
// Anything except '\0' is an octal escape sequence, illegal in strict mode.
// Remember the position of octal escape sequences so that an error
// can be reported later (in strict mode).
// We don't report the error immediately, because the octal escape can
// occur before the "use strict" directive.
if (c != '0' || i > 0) {
octal_pos_ = Location(source_pos() - i - 1, source_pos() - 1);
}
return x;
}
Token::Value Scanner::ScanString() {
uc32 quote = c0_;
Advance(); // consume quote
LiteralScope literal(this);
while (c0_ != quote && c0_ >= 0
&& !unicode_cache_->IsLineTerminator(c0_)) {
uc32 c = c0_;
Advance();
if (c == '\\') {
if (c0_ < 0 || !ScanEscape()) return Token::ILLEGAL;
} else {
AddLiteralChar(c);
}
}
if (c0_ != quote) return Token::ILLEGAL;
literal.Complete();
Advance(); // consume quote
return Token::STRING;
}
void Scanner::ScanDecimalDigits() {
while (IsDecimalDigit(c0_))
AddLiteralCharAdvance();
}
Token::Value Scanner::ScanNumber(bool seen_period) {
ASSERT(IsDecimalDigit(c0_)); // the first digit of the number or the fraction
enum { DECIMAL, HEX, OCTAL } kind = DECIMAL;
LiteralScope literal(this);
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') {
int start_pos = source_pos(); // For reporting octal positions.
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 (!IsHexDigit(c0_)) {
// we must have at least one hex digit after 'x'/'X'
return Token::ILLEGAL;
}
while (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_) {
// Octal literal finished.
octal_pos_ = Location(start_pos, source_pos());
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 Token::ILLEGAL; // no exponent for octals allowed
// scan exponent
AddLiteralCharAdvance();
if (c0_ == '+' || c0_ == '-')
AddLiteralCharAdvance();
if (!IsDecimalDigit(c0_)) {
// 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(c0_) || unicode_cache_->IsIdentifierStart(c0_))
return Token::ILLEGAL;
literal.Complete();
return Token::NUMBER;
}
uc32 Scanner::ScanIdentifierUnicodeEscape() {
Advance();
if (c0_ != 'u') return -1;
Advance();
uc32 result = ScanHexNumber(4);
if (result < 0) PushBack('u');
return result;
}
// ----------------------------------------------------------------------------
// 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("class", Token::FUTURE_RESERVED_WORD) \
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("export", harmony_modules \
? Token::EXPORT : Token::FUTURE_RESERVED_WORD) \
KEYWORD("extends", 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("import", harmony_modules \
? Token::IMPORT : Token::FUTURE_RESERVED_WORD) \
KEYWORD("in", Token::IN) \
KEYWORD("instanceof", Token::INSTANCEOF) \
KEYWORD("interface", Token::FUTURE_STRICT_RESERVED_WORD) \
KEYWORD_GROUP('l') \
KEYWORD("let", harmony_scoping \
? Token::LET : Token::FUTURE_STRICT_RESERVED_WORD) \
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("static", Token::FUTURE_STRICT_RESERVED_WORD) \
KEYWORD("super", Token::FUTURE_RESERVED_WORD) \
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) \
KEYWORD_GROUP('y') \
KEYWORD("yield", Token::FUTURE_STRICT_RESERVED_WORD)
static Token::Value KeywordOrIdentifierToken(const char* input,
int input_length,
bool harmony_scoping,
bool harmony_modules) {
ASSERT(input_length >= 1);
const int kMinLength = 2;
const int kMaxLength = 10;
if (input_length < kMinLength || input_length > 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; \
STATIC_ASSERT(keyword_length >= kMinLength); \
STATIC_ASSERT(keyword_length <= kMaxLength); \
if (input_length == keyword_length && \
input[1] == keyword[1] && \
(keyword_length <= 2 || input[2] == keyword[2]) && \
(keyword_length <= 3 || input[3] == keyword[3]) && \
(keyword_length <= 4 || input[4] == keyword[4]) && \
(keyword_length <= 5 || input[5] == keyword[5]) && \
(keyword_length <= 6 || input[6] == keyword[6]) && \
(keyword_length <= 7 || input[7] == keyword[7]) && \
(keyword_length <= 8 || input[8] == keyword[8]) && \
(keyword_length <= 9 || input[9] == keyword[9])) { \
return token; \
} \
}
KEYWORDS(KEYWORD_GROUP_CASE, KEYWORD)
}
return Token::IDENTIFIER;
}
Token::Value Scanner::ScanIdentifierOrKeyword() {
ASSERT(unicode_cache_->IsIdentifierStart(c0_));
LiteralScope literal(this);
// Scan identifier start character.
if (c0_ == '\\') {
uc32 c = ScanIdentifierUnicodeEscape();
// Only allow legal identifier start characters.
if (c < 0 ||
c == '\\' || // No recursive escapes.
!unicode_cache_->IsIdentifierStart(c)) {
return Token::ILLEGAL;
}
AddLiteralChar(c);
return ScanIdentifierSuffix(&literal);
}
uc32 first_char = c0_;
Advance();
AddLiteralChar(first_char);
// Scan the rest of the identifier characters.
while (unicode_cache_->IsIdentifierPart(c0_)) {
if (c0_ != '\\') {
uc32 next_char = c0_;
Advance();
AddLiteralChar(next_char);
continue;
}
// Fallthrough if no longer able to complete keyword.
return ScanIdentifierSuffix(&literal);
}
literal.Complete();
if (next_.literal_chars->is_ascii()) {
Vector<const char> chars = next_.literal_chars->ascii_literal();
return KeywordOrIdentifierToken(chars.start(),
chars.length(),
harmony_scoping_,
harmony_modules_);
}
return Token::IDENTIFIER;
}
Token::Value Scanner::ScanIdentifierSuffix(LiteralScope* literal) {
// Scan the rest of the identifier characters.
while (unicode_cache_->IsIdentifierPart(c0_)) {
if (c0_ == '\\') {
uc32 c = ScanIdentifierUnicodeEscape();
// Only allow legal identifier part characters.
if (c < 0 ||
c == '\\' ||
!unicode_cache_->IsIdentifierPart(c)) {
return Token::ILLEGAL;
}
AddLiteralChar(c);
} else {
AddLiteralChar(c0_);
Advance();
}
}
literal->Complete();
return Token::IDENTIFIER;
}
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);
if (seen_equal) {
AddLiteralChar('=');
}
while (c0_ != '/' || in_character_class) {
if (unicode_cache_->IsLineTerminator(c0_) || c0_ < 0) return false;
if (c0_ == '\\') { // Escape sequence.
AddLiteralCharAdvance();
if (unicode_cache_->IsLineTerminator(c0_) || c0_ < 0) return false;
AddLiteralCharAdvance();
// If the escape allows more characters, i.e., \x??, \u????, or \c?,
// only "safe" characters are allowed (letters, digits, underscore),
// otherwise the escape isn't valid and the invalid character has
// its normal meaning. I.e., we can just continue scanning without
// worrying whether the following characters are part of the escape
// or not, since any '/', '\\' or '[' is guaranteed to not be part
// of the escape sequence.
// TODO(896): At some point, parse RegExps more throughly to capture
// octal esacpes in strict mode.
} else { // Unescaped character.
if (c0_ == '[') in_character_class = true;
if (c0_ == ']') in_character_class = false;
AddLiteralCharAdvance();
}
}
Advance(); // consume '/'
literal.Complete();
return true;
}
bool Scanner::ScanLiteralUnicodeEscape() {
ASSERT(c0_ == '\\');
uc32 chars_read[6] = {'\\', 'u', 0, 0, 0, 0};
Advance();
int i = 1;
if (c0_ == 'u') {
i++;
while (i < 6) {
Advance();
if (!IsHexDigit(c0_)) break;
chars_read[i] = c0_;
i++;
}
}
if (i < 6) {
// Incomplete escape. Undo all advances and return false.
while (i > 0) {
i--;
PushBack(chars_read[i]);
}
return false;
}
// Complete escape. Add all chars to current literal buffer.
for (int i = 0; i < 6; i++) {
AddLiteralChar(chars_read[i]);
}
return true;
}
bool Scanner::ScanRegExpFlags() {
// Scan regular expression flags.
LiteralScope literal(this);
while (unicode_cache_->IsIdentifierPart(c0_)) {
if (c0_ != '\\') {
AddLiteralCharAdvance();
} else {
if (!ScanLiteralUnicodeEscape()) {
break;
}
}
}
literal.Complete();
next_.location.end_pos = source_pos() - 1;
return true;
}
} } // namespace v8::internal
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