80fecc615a
Implement the syntax and behavor necessary to support array literals such as [...[1, 2, 3]]. A type error is thrown if the target of the spread operator does not evaluate to an array (though it should eventually just check for an iterable). Note that the spread token's name is TripleDot, since the '...' token is used for two features: spread and rest. Calling it anything involving 'spread' or 'rest' would be a bit confusing.
427 lines
15 KiB
C++
427 lines
15 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 "Lexer.h"
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#include <AK/HashMap.h>
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#include <AK/StringBuilder.h>
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#include <ctype.h>
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#include <stdio.h>
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namespace JS {
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HashMap<String, TokenType> Lexer::s_keywords;
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HashMap<String, TokenType> Lexer::s_three_char_tokens;
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HashMap<String, TokenType> Lexer::s_two_char_tokens;
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HashMap<char, TokenType> Lexer::s_single_char_tokens;
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Lexer::Lexer(StringView source)
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: m_source(source)
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, m_current_token(TokenType::Eof, StringView(nullptr), StringView(nullptr), 0, 0)
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{
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if (s_keywords.is_empty()) {
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s_keywords.set("await", TokenType::Await);
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s_keywords.set("break", TokenType::Break);
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s_keywords.set("case", TokenType::Case);
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s_keywords.set("catch", TokenType::Catch);
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s_keywords.set("class", TokenType::Class);
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s_keywords.set("const", TokenType::Const);
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s_keywords.set("continue", TokenType::Continue);
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s_keywords.set("default", TokenType::Default);
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s_keywords.set("delete", TokenType::Delete);
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s_keywords.set("do", TokenType::Do);
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s_keywords.set("else", TokenType::Else);
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s_keywords.set("false", TokenType::BoolLiteral);
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s_keywords.set("finally", TokenType::Finally);
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s_keywords.set("for", TokenType::For);
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s_keywords.set("function", TokenType::Function);
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s_keywords.set("if", TokenType::If);
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s_keywords.set("in", TokenType::In);
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s_keywords.set("instanceof", TokenType::Instanceof);
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s_keywords.set("interface", TokenType::Interface);
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s_keywords.set("let", TokenType::Let);
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s_keywords.set("new", TokenType::New);
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s_keywords.set("null", TokenType::NullLiteral);
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s_keywords.set("return", TokenType::Return);
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s_keywords.set("switch", TokenType::Switch);
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s_keywords.set("this", TokenType::This);
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s_keywords.set("throw", TokenType::Throw);
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s_keywords.set("true", TokenType::BoolLiteral);
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s_keywords.set("try", TokenType::Try);
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s_keywords.set("typeof", TokenType::Typeof);
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s_keywords.set("var", TokenType::Var);
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s_keywords.set("void", TokenType::Void);
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s_keywords.set("while", TokenType::While);
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s_keywords.set("yield", TokenType::Yield);
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}
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if (s_three_char_tokens.is_empty()) {
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s_three_char_tokens.set("===", TokenType::EqualsEqualsEquals);
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s_three_char_tokens.set("!==", TokenType::ExclamationMarkEqualsEquals);
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s_three_char_tokens.set("**=", TokenType::AsteriskAsteriskEquals);
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s_three_char_tokens.set("<<=", TokenType::ShiftLeftEquals);
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s_three_char_tokens.set(">>=", TokenType::ShiftRightEquals);
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s_three_char_tokens.set(">>>", TokenType::UnsignedShiftRight);
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s_three_char_tokens.set("...", TokenType::TripleDot);
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}
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if (s_two_char_tokens.is_empty()) {
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s_two_char_tokens.set("=>", TokenType::Arrow);
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s_two_char_tokens.set("+=", TokenType::PlusEquals);
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s_two_char_tokens.set("-=", TokenType::MinusEquals);
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s_two_char_tokens.set("*=", TokenType::AsteriskEquals);
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s_two_char_tokens.set("/=", TokenType::SlashEquals);
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s_two_char_tokens.set("%=", TokenType::PercentEquals);
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s_two_char_tokens.set("&=", TokenType::AmpersandEquals);
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s_two_char_tokens.set("|=", TokenType::PipeEquals);
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s_two_char_tokens.set("&&", TokenType::DoubleAmpersand);
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s_two_char_tokens.set("||", TokenType::DoublePipe);
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s_two_char_tokens.set("??", TokenType::DoubleQuestionMark);
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s_two_char_tokens.set("**", TokenType::DoubleAsterisk);
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s_two_char_tokens.set("==", TokenType::EqualsEquals);
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s_two_char_tokens.set("<=", TokenType::LessThanEquals);
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s_two_char_tokens.set(">=", TokenType::GreaterThanEquals);
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s_two_char_tokens.set("!=", TokenType::ExclamationMarkEquals);
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s_two_char_tokens.set("--", TokenType::MinusMinus);
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s_two_char_tokens.set("++", TokenType::PlusPlus);
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s_two_char_tokens.set("<<", TokenType::ShiftLeft);
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s_two_char_tokens.set(">>", TokenType::ShiftRight);
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s_two_char_tokens.set("?.", TokenType::QuestionMarkPeriod);
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}
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if (s_single_char_tokens.is_empty()) {
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s_single_char_tokens.set('&', TokenType::Ampersand);
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s_single_char_tokens.set('*', TokenType::Asterisk);
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s_single_char_tokens.set('[', TokenType::BracketOpen);
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s_single_char_tokens.set(']', TokenType::BracketClose);
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s_single_char_tokens.set('^', TokenType::Caret);
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s_single_char_tokens.set(':', TokenType::Colon);
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s_single_char_tokens.set(',', TokenType::Comma);
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s_single_char_tokens.set('{', TokenType::CurlyOpen);
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s_single_char_tokens.set('}', TokenType::CurlyClose);
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s_single_char_tokens.set('=', TokenType::Equals);
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s_single_char_tokens.set('!', TokenType::ExclamationMark);
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s_single_char_tokens.set('-', TokenType::Minus);
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s_single_char_tokens.set('(', TokenType::ParenOpen);
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s_single_char_tokens.set(')', TokenType::ParenClose);
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s_single_char_tokens.set('%', TokenType::Percent);
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s_single_char_tokens.set('.', TokenType::Period);
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s_single_char_tokens.set('|', TokenType::Pipe);
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s_single_char_tokens.set('+', TokenType::Plus);
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s_single_char_tokens.set('?', TokenType::QuestionMark);
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s_single_char_tokens.set(';', TokenType::Semicolon);
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s_single_char_tokens.set('/', TokenType::Slash);
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s_single_char_tokens.set('~', TokenType::Tilde);
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s_single_char_tokens.set('<', TokenType::LessThan);
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s_single_char_tokens.set('>', TokenType::GreaterThan);
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}
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consume();
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}
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void Lexer::consume()
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{
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if (m_position >= m_source.length()) {
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m_position = m_source.length() + 1;
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m_current_char = EOF;
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return;
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}
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if (m_current_char == '\n') {
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m_line_number++;
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m_line_column = 1;
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} else {
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m_line_column++;
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}
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m_current_char = m_source[m_position++];
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}
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void Lexer::consume_exponent()
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{
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consume();
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if (m_current_char == '-' || m_current_char == '+')
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consume();
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while (isdigit(m_current_char)) {
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consume();
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}
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}
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bool Lexer::match(char a, char b) const
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{
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if (m_position >= m_source.length())
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return false;
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return m_current_char == a
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&& m_source[m_position] == b;
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}
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bool Lexer::match(char a, char b, char c) const
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{
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if (m_position + 1 >= m_source.length())
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return false;
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return m_current_char == a
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&& m_source[m_position] == b
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&& m_source[m_position + 1] == c;
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}
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bool Lexer::match(char a, char b, char c, char d) const
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{
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if (m_position + 2 >= m_source.length())
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return false;
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return m_current_char == a
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&& m_source[m_position] == b
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&& m_source[m_position + 1] == c
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&& m_source[m_position + 2] == d;
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}
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bool Lexer::is_eof() const
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{
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return m_current_char == EOF;
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}
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bool Lexer::is_identifier_start() const
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{
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return isalpha(m_current_char) || m_current_char == '_' || m_current_char == '$';
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}
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bool Lexer::is_identifier_middle() const
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{
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return is_identifier_start() || isdigit(m_current_char);
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}
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bool Lexer::is_line_comment_start() const
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{
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return match('/', '/') || match('<', '!', '-', '-') || match('-', '-', '>');
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}
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bool Lexer::is_block_comment_start() const
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{
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return match('/', '*');
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}
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bool Lexer::is_block_comment_end() const
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{
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return match('*', '/');
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}
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bool Lexer::is_numeric_literal_start() const
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{
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return isdigit(m_current_char) || (m_current_char == '.' && m_position < m_source.length() && isdigit(m_source[m_position]));
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}
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void Lexer::syntax_error(const char* msg)
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{
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m_has_errors = true;
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if (m_log_errors)
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fprintf(stderr, "Syntax Error: %s (line: %zu, column: %zu)\n", msg, m_line_number, m_line_column);
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}
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Token Lexer::next()
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{
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size_t trivia_start = m_position;
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// consume whitespace and comments
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while (true) {
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if (isspace(m_current_char)) {
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do {
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consume();
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} while (isspace(m_current_char));
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} else if (is_line_comment_start()) {
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consume();
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do {
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consume();
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} while (!is_eof() && m_current_char != '\n');
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} else if (is_block_comment_start()) {
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consume();
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do {
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consume();
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} while (!is_eof() && !is_block_comment_end());
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consume(); // consume *
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consume(); // consume /
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} else {
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break;
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}
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}
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size_t value_start = m_position;
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auto token_type = TokenType::Invalid;
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if (is_identifier_start()) {
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// identifier or keyword
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do {
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consume();
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} while (is_identifier_middle());
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StringView value = m_source.substring_view(value_start - 1, m_position - value_start);
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auto it = s_keywords.find(value);
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if (it == s_keywords.end()) {
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token_type = TokenType::Identifier;
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} else {
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token_type = it->value;
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}
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} else if (is_numeric_literal_start()) {
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if (m_current_char == '0') {
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consume();
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if (m_current_char == '.') {
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// decimal
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consume();
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while (isdigit(m_current_char)) {
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consume();
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}
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if (m_current_char == 'e' || m_current_char == 'E') {
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consume_exponent();
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}
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} else if (m_current_char == 'e' || m_current_char == 'E') {
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consume_exponent();
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} else if (m_current_char == 'o' || m_current_char == 'O') {
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// octal
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consume();
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while (m_current_char >= '0' && m_current_char <= '7') {
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consume();
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}
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} else if (m_current_char == 'b' || m_current_char == 'B') {
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// binary
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consume();
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while (m_current_char == '0' || m_current_char == '1') {
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consume();
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}
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} else if (m_current_char == 'x' || m_current_char == 'X') {
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// hexadecimal
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consume();
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while (isxdigit(m_current_char)) {
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consume();
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}
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} else if (isdigit(m_current_char)) {
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// octal without 'O' prefix. Forbidden in 'strict mode'
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// FIXME: We need to make sure this produces a syntax error when in strict mode
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do {
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consume();
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} while (isdigit(m_current_char));
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}
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} else {
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// 1...9 or period
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while (isdigit(m_current_char)) {
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consume();
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}
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if (m_current_char == '.') {
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consume();
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while (isdigit(m_current_char)) {
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consume();
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}
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}
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if (m_current_char == 'e' || m_current_char == 'E') {
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consume_exponent();
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}
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}
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token_type = TokenType::NumericLiteral;
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} else if (m_current_char == '"' || m_current_char == '\'' || m_current_char == '`') {
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char stop_char = m_current_char;
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consume();
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while (m_current_char != stop_char && m_current_char != '\n' && !is_eof()) {
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if (m_current_char == '\\') {
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consume();
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}
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consume();
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}
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if (m_current_char != stop_char) {
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syntax_error("unterminated string literal");
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token_type = TokenType::UnterminatedStringLiteral;
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} else {
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consume();
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if (stop_char == '`')
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token_type = TokenType::TemplateLiteral;
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else
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token_type = TokenType::StringLiteral;
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}
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} else if (m_current_char == EOF) {
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token_type = TokenType::Eof;
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} else {
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// There is only one four-char operator: >>>=
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bool found_four_char_token = false;
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if (match('>', '>', '>', '=')) {
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found_four_char_token = true;
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consume();
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consume();
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consume();
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consume();
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token_type = TokenType::UnsignedShiftRightEquals;
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}
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bool found_three_char_token = false;
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if (!found_four_char_token && m_position + 1 < m_source.length()) {
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char second_char = m_source[m_position];
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char third_char = m_source[m_position + 1];
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char three_chars[] { (char)m_current_char, second_char, third_char, 0 };
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auto it = s_three_char_tokens.find(three_chars);
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if (it != s_three_char_tokens.end()) {
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found_three_char_token = true;
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consume();
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consume();
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consume();
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token_type = it->value;
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}
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}
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bool found_two_char_token = false;
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if (!found_four_char_token && !found_three_char_token && m_position < m_source.length()) {
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char second_char = m_source[m_position];
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char two_chars[] { (char)m_current_char, second_char, 0 };
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auto it = s_two_char_tokens.find(two_chars);
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if (it != s_two_char_tokens.end()) {
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found_two_char_token = true;
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consume();
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consume();
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token_type = it->value;
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}
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}
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bool found_one_char_token = false;
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if (!found_four_char_token && !found_three_char_token && !found_two_char_token) {
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auto it = s_single_char_tokens.find(m_current_char);
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if (it != s_single_char_tokens.end()) {
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found_one_char_token = true;
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consume();
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token_type = it->value;
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}
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}
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if (!found_four_char_token && !found_three_char_token && !found_two_char_token && !found_one_char_token) {
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consume();
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token_type = TokenType::Invalid;
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}
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}
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m_current_token = Token(
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token_type,
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m_source.substring_view(trivia_start - 1, value_start - trivia_start),
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m_source.substring_view(value_start - 1, m_position - value_start),
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m_line_number,
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m_line_column - m_position + value_start);
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return m_current_token;
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}
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}
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