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			242 lines
		
	
	
	
		
			8.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			242 lines
		
	
	
	
		
			8.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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 * Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@gmx.de>
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright notice, this
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 *    list of conditions and the following disclaimer.
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 *
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 *    this list of conditions and the following disclaimer in the documentation
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 *    and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include "Token.h"
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#include <AK/Assertions.h>
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#include <AK/StringBuilder.h>
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#include <AK/Utf32View.h>
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#include <ctype.h>
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namespace JS {
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const char* Token::name(TokenType type)
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{
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    switch (type) {
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#define __ENUMERATE_JS_TOKEN(x) \
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    case TokenType::x:          \
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        return #x;
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        ENUMERATE_JS_TOKENS
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#undef __ENUMERATE_JS_TOKEN
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    default:
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        ASSERT_NOT_REACHED();
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        return "<Unknown>";
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    }
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}
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const char* Token::name() const
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{
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    return name(m_type);
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}
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double Token::double_value() const
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{
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    ASSERT(type() == TokenType::NumericLiteral);
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    String value_string(m_value);
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    if (value_string[0] == '0' && value_string.length() >= 2) {
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        if (value_string[1] == 'x' || value_string[1] == 'X') {
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            // hexadecimal
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            return static_cast<double>(strtoul(value_string.characters() + 2, nullptr, 16));
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        } else if (value_string[1] == 'o' || value_string[1] == 'O') {
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            // octal
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            return static_cast<double>(strtoul(value_string.characters() + 2, nullptr, 8));
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        } else if (value_string[1] == 'b' || value_string[1] == 'B') {
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            // binary
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            return static_cast<double>(strtoul(value_string.characters() + 2, nullptr, 2));
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        } else if (isdigit(value_string[1])) {
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            // also octal, but syntax error in strict mode
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            return static_cast<double>(strtoul(value_string.characters() + 1, nullptr, 8));
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        }
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    }
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    return strtod(value_string.characters(), nullptr);
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}
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static u32 hex2int(char x)
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{
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    ASSERT(isxdigit(x));
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    if (x >= '0' && x <= '9')
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        return x - '0';
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    return 10u + (tolower(x) - 'a');
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}
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String Token::string_value(StringValueStatus& status) const
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{
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    ASSERT(type() == TokenType::StringLiteral || type() == TokenType::TemplateLiteralString);
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    auto is_template = type() == TokenType::TemplateLiteralString;
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    auto offset = type() == TokenType::TemplateLiteralString ? 0 : 1;
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    auto encoding_failure = [&status](StringValueStatus parse_status) -> String {
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        status = parse_status;
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        return {};
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    };
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    StringBuilder builder;
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    for (size_t i = offset; i < m_value.length() - offset; ++i) {
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        if (m_value[i] == '\\' && i + 1 < m_value.length() - offset) {
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            i++;
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            switch (m_value[i]) {
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            case 'b':
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                builder.append('\b');
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                break;
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            case 'f':
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                builder.append('\f');
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                break;
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            case 'n':
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                builder.append('\n');
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                break;
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            case 'r':
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                builder.append('\r');
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                break;
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            case 't':
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                builder.append('\t');
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                break;
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            case 'v':
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                builder.append('\v');
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                break;
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            case '0':
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                builder.append((char)0);
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                break;
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            case '\'':
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                builder.append('\'');
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                break;
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            case '"':
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                builder.append('"');
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                break;
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            case '\\':
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                builder.append('\\');
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                break;
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            case 'x': {
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                if (i + 2 >= m_value.length() - offset)
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                    return encoding_failure(StringValueStatus::MalformedHexEscape);
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                auto digit1 = m_value[++i];
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                auto digit2 = m_value[++i];
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                if (!isxdigit(digit1) || !isxdigit(digit2))
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                    return encoding_failure(StringValueStatus::MalformedHexEscape);
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                builder.append(static_cast<char>(hex2int(digit1) * 16 + hex2int(digit2)));
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                break;
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            }
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            case 'u': {
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                if (i + 1 >= m_value.length() - offset)
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                    return encoding_failure(StringValueStatus::MalformedUnicodeEscape);
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                u32 code_point = m_value[++i];
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                if (code_point == '{') {
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                    code_point = 0;
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                    while (true) {
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                        if (i + 1 >= m_value.length() - offset)
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                            return encoding_failure(StringValueStatus::MalformedUnicodeEscape);
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                        auto ch = m_value[++i];
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                        if (ch == '}')
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                            break;
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                        if (!isxdigit(ch))
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                            return encoding_failure(StringValueStatus::MalformedUnicodeEscape);
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                        auto new_code_point = (code_point << 4u) | hex2int(ch);
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                        if (new_code_point < code_point)
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                            return encoding_failure(StringValueStatus::UnicodeEscapeOverflow);
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                        code_point = new_code_point;
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                    }
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                } else {
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                    if (i + 3 >= m_value.length() - offset || !isxdigit(code_point))
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                        return encoding_failure(StringValueStatus::MalformedUnicodeEscape);
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                    code_point = hex2int(code_point);
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                    for (int j = 0; j < 3; ++j) {
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                        auto ch = m_value[++i];
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                        if (!isxdigit(ch))
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                            return encoding_failure(StringValueStatus::MalformedUnicodeEscape);
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                        code_point = (code_point << 4u) | hex2int(ch);
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                    }
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                }
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                builder.append({ &code_point, 1 });
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                break;
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            }
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            default:
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                if (is_template && (m_value[i] == '$' || m_value[i] == '`')) {
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                    builder.append(m_value[i]);
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                    break;
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                }
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                // FIXME: Also parse octal. Should anything else generate a syntax error?
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                builder.append(m_value[i]);
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            }
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        } else {
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            builder.append(m_value[i]);
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        }
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    }
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    return builder.to_string();
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}
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bool Token::bool_value() const
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{
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    ASSERT(type() == TokenType::BoolLiteral);
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    return m_value == "true";
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}
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bool Token::is_identifier_name() const
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{
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    // IdentifierNames are Identifiers + ReservedWords
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    // The standard defines this reversed: Identifiers are IdentifierNames except reserved words
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    // https://www.ecma-international.org/ecma-262/5.1/#sec-7.6
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    return m_type == TokenType::Identifier
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        || m_type == TokenType::Await
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        || m_type == TokenType::BoolLiteral
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        || m_type == TokenType::Break
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        || m_type == TokenType::Case
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        || m_type == TokenType::Catch
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        || m_type == TokenType::Class
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        || m_type == TokenType::Const
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        || m_type == TokenType::Continue
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        || m_type == TokenType::Default
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        || m_type == TokenType::Delete
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        || m_type == TokenType::Do
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        || m_type == TokenType::Else
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        || m_type == TokenType::Finally
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        || m_type == TokenType::For
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        || m_type == TokenType::Function
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        || m_type == TokenType::If
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        || m_type == TokenType::In
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        || m_type == TokenType::Instanceof
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        || m_type == TokenType::Interface
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        || m_type == TokenType::Let
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        || m_type == TokenType::New
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        || m_type == TokenType::NullLiteral
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        || m_type == TokenType::Return
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        || m_type == TokenType::Switch
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        || m_type == TokenType::This
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        || m_type == TokenType::Throw
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        || m_type == TokenType::Try
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        || m_type == TokenType::Typeof
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        || m_type == TokenType::Var
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        || m_type == TokenType::Void
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        || m_type == TokenType::While
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        || m_type == TokenType::Yield;
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}
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}
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