ladybird/Userland/Libraries/LibJS/Parser.cpp
Daniel Bertalan d7b6cc6421 Everywhere: Prevent risky implicit casts of (Nonnull)RefPtr
Our existing implementation did not check the element type of the other
pointer in the constructors and move assignment operators. This meant
that some operations that would require explicit casting on raw pointers
were done implicitly, such as:
- downcasting a base class to a derived class (e.g. `Kernel::Inode` =>
  `Kernel::ProcFSDirectoryInode` in Kernel/ProcFS.cpp),
- casting to an unrelated type (e.g. `Promise<bool>` => `Promise<Empty>`
  in LibIMAP/Client.cpp)

This, of course, allows gross violations of the type system, and makes
the need to type-check less obvious before downcasting. Luckily, while
adding the `static_ptr_cast`s, only two truly incorrect usages were
found; in the other instances, our casts just needed to be made
explicit.
2021-09-03 23:20:23 +02:00

3407 lines
142 KiB
C++

/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
* Copyright (c) 2020-2021, Linus Groh <linusg@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Parser.h"
#include <AK/Array.h>
#include <AK/CharacterTypes.h>
#include <AK/HashTable.h>
#include <AK/ScopeGuard.h>
#include <AK/StdLibExtras.h>
#include <AK/TemporaryChange.h>
#include <LibJS/Runtime/RegExpObject.h>
#include <LibRegex/Regex.h>
namespace JS {
static bool statement_is_use_strict_directive(NonnullRefPtr<Statement> statement)
{
if (!is<ExpressionStatement>(*statement))
return false;
auto& expression_statement = static_cast<ExpressionStatement&>(*statement);
auto& expression = expression_statement.expression();
if (!is<StringLiteral>(expression))
return false;
return static_cast<const StringLiteral&>(expression).is_use_strict_directive();
}
class ScopePusher {
public:
enum Type {
Var = 1,
Let = 2,
};
ScopePusher(Parser& parser, unsigned mask, Parser::Scope::Type scope_type)
: m_parser(parser)
, m_mask(mask)
{
if (m_mask & Var)
m_parser.m_state.var_scopes.append(NonnullRefPtrVector<VariableDeclaration>());
if (m_mask & Let)
m_parser.m_state.let_scopes.append(NonnullRefPtrVector<VariableDeclaration>());
m_parser.m_state.current_scope = make_ref_counted<Parser::Scope>(scope_type, m_parser.m_state.current_scope);
}
~ScopePusher()
{
if (m_mask & Var)
m_parser.m_state.var_scopes.take_last();
if (m_mask & Let)
m_parser.m_state.let_scopes.take_last();
auto& popped = m_parser.m_state.current_scope;
// Manual clear required to resolve circular references
popped->hoisted_function_declarations.clear();
m_parser.m_state.current_scope = popped->parent;
}
void add_to_scope_node(NonnullRefPtr<ScopeNode> scope_node)
{
if (m_mask & Var)
scope_node->add_variables(m_parser.m_state.var_scopes.last());
if (m_mask & Let)
scope_node->add_variables(m_parser.m_state.let_scopes.last());
auto& scope = m_parser.m_state.current_scope;
scope_node->add_functions(scope->function_declarations);
for (auto& hoistable_function : scope->hoisted_function_declarations) {
if (is_hoistable(hoistable_function)) {
scope_node->add_hoisted_function(hoistable_function.declaration);
}
}
}
static bool is_hoistable(Parser::Scope::HoistableDeclaration& declaration)
{
auto& name = declaration.declaration->name();
// See if we find any conflicting lexical declaration on the way up
for (RefPtr<Parser::Scope> scope = declaration.scope; !scope.is_null(); scope = scope->parent) {
if (scope->lexical_declarations.contains(name)) {
return false;
}
}
return true;
}
Parser& m_parser;
unsigned m_mask { 0 };
};
class OperatorPrecedenceTable {
public:
constexpr OperatorPrecedenceTable()
: m_token_precedence()
{
for (size_t i = 0; i < array_size(m_operator_precedence); ++i) {
auto& op = m_operator_precedence[i];
m_token_precedence[static_cast<size_t>(op.token)] = op.precedence;
}
}
constexpr int get(TokenType token) const
{
int p = m_token_precedence[static_cast<size_t>(token)];
if (p == 0) {
warnln("Internal Error: No precedence for operator {}", Token::name(token));
VERIFY_NOT_REACHED();
return -1;
}
return p;
}
private:
int m_token_precedence[cs_num_of_js_tokens];
struct OperatorPrecedence {
TokenType token;
int precedence;
};
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
static constexpr const OperatorPrecedence m_operator_precedence[] = {
{ TokenType::Period, 20 },
{ TokenType::BracketOpen, 20 },
{ TokenType::ParenOpen, 20 },
{ TokenType::QuestionMarkPeriod, 20 },
{ TokenType::New, 19 },
{ TokenType::PlusPlus, 18 },
{ TokenType::MinusMinus, 18 },
{ TokenType::ExclamationMark, 17 },
{ TokenType::Tilde, 17 },
{ TokenType::Typeof, 17 },
{ TokenType::Void, 17 },
{ TokenType::Delete, 17 },
{ TokenType::Await, 17 },
{ TokenType::DoubleAsterisk, 16 },
{ TokenType::Asterisk, 15 },
{ TokenType::Slash, 15 },
{ TokenType::Percent, 15 },
{ TokenType::Plus, 14 },
{ TokenType::Minus, 14 },
{ TokenType::ShiftLeft, 13 },
{ TokenType::ShiftRight, 13 },
{ TokenType::UnsignedShiftRight, 13 },
{ TokenType::LessThan, 12 },
{ TokenType::LessThanEquals, 12 },
{ TokenType::GreaterThan, 12 },
{ TokenType::GreaterThanEquals, 12 },
{ TokenType::In, 12 },
{ TokenType::Instanceof, 12 },
{ TokenType::EqualsEquals, 11 },
{ TokenType::ExclamationMarkEquals, 11 },
{ TokenType::EqualsEqualsEquals, 11 },
{ TokenType::ExclamationMarkEqualsEquals, 11 },
{ TokenType::Ampersand, 10 },
{ TokenType::Caret, 9 },
{ TokenType::Pipe, 8 },
{ TokenType::DoubleQuestionMark, 7 },
{ TokenType::DoubleAmpersand, 6 },
{ TokenType::DoublePipe, 5 },
{ TokenType::QuestionMark, 4 },
{ TokenType::Equals, 3 },
{ TokenType::PlusEquals, 3 },
{ TokenType::MinusEquals, 3 },
{ TokenType::DoubleAsteriskEquals, 3 },
{ TokenType::AsteriskEquals, 3 },
{ TokenType::SlashEquals, 3 },
{ TokenType::PercentEquals, 3 },
{ TokenType::ShiftLeftEquals, 3 },
{ TokenType::ShiftRightEquals, 3 },
{ TokenType::UnsignedShiftRightEquals, 3 },
{ TokenType::AmpersandEquals, 3 },
{ TokenType::CaretEquals, 3 },
{ TokenType::PipeEquals, 3 },
{ TokenType::DoubleAmpersandEquals, 3 },
{ TokenType::DoublePipeEquals, 3 },
{ TokenType::DoubleQuestionMarkEquals, 3 },
{ TokenType::Yield, 2 },
{ TokenType::Comma, 1 },
};
};
constexpr OperatorPrecedenceTable g_operator_precedence;
Parser::ParserState::ParserState(Lexer l, Program::Type program_type)
: lexer(move(l))
{
if (program_type == Program::Type::Module)
lexer.disallow_html_comments();
current_token = lexer.next();
}
Parser::Scope::Scope(Parser::Scope::Type type, RefPtr<Parser::Scope> parent_scope)
: type(type)
, parent(move(parent_scope))
{
}
RefPtr<Parser::Scope> Parser::Scope::get_current_function_scope()
{
if (this->type == Parser::Scope::Function) {
return *this;
}
auto result = this->parent;
while (result->type != Parser::Scope::Function) {
result = result->parent;
}
return result;
}
Parser::Parser(Lexer lexer, Program::Type program_type)
: m_state(move(lexer), program_type)
, m_program_type(program_type)
{
}
Associativity Parser::operator_associativity(TokenType type) const
{
switch (type) {
case TokenType::Period:
case TokenType::BracketOpen:
case TokenType::ParenOpen:
case TokenType::QuestionMarkPeriod:
case TokenType::Asterisk:
case TokenType::Slash:
case TokenType::Percent:
case TokenType::Plus:
case TokenType::Minus:
case TokenType::ShiftLeft:
case TokenType::ShiftRight:
case TokenType::UnsignedShiftRight:
case TokenType::LessThan:
case TokenType::LessThanEquals:
case TokenType::GreaterThan:
case TokenType::GreaterThanEquals:
case TokenType::In:
case TokenType::Instanceof:
case TokenType::EqualsEquals:
case TokenType::ExclamationMarkEquals:
case TokenType::EqualsEqualsEquals:
case TokenType::ExclamationMarkEqualsEquals:
case TokenType::Typeof:
case TokenType::Void:
case TokenType::Delete:
case TokenType::Ampersand:
case TokenType::Caret:
case TokenType::Pipe:
case TokenType::DoubleQuestionMark:
case TokenType::DoubleAmpersand:
case TokenType::DoublePipe:
case TokenType::Comma:
return Associativity::Left;
default:
return Associativity::Right;
}
}
NonnullRefPtr<Program> Parser::parse_program(bool starts_in_strict_mode)
{
auto rule_start = push_start();
ScopePusher scope(*this, ScopePusher::Var | ScopePusher::Let, Scope::Function);
auto program = adopt_ref(*new Program({ m_filename, rule_start.position(), position() }, m_program_type));
if (starts_in_strict_mode || m_program_type == Program::Type::Module) {
program->set_strict_mode();
m_state.strict_mode = true;
}
bool parsing_directives = true;
while (!done()) {
if (match_declaration()) {
program->append(parse_declaration());
parsing_directives = false;
} else if (match_statement()) {
auto statement = parse_statement(AllowLabelledFunction::Yes);
program->append(statement);
if (statement_is_use_strict_directive(statement)) {
if (parsing_directives) {
program->set_strict_mode();
m_state.strict_mode = true;
}
if (m_state.string_legacy_octal_escape_sequence_in_scope)
syntax_error("Octal escape sequence in string literal not allowed in strict mode");
}
if (parsing_directives && is<ExpressionStatement>(*statement)) {
auto& expression_statement = static_cast<ExpressionStatement&>(*statement);
auto& expression = expression_statement.expression();
parsing_directives = is<StringLiteral>(expression);
} else {
parsing_directives = false;
}
} else if (match_export_or_import()) {
VERIFY(m_state.current_token.type() == TokenType::Export || m_state.current_token.type() == TokenType::Import);
if (m_state.current_token.type() == TokenType::Export)
program->append_export(parse_export_statement(*program));
else
program->append_import(parse_import_statement(*program));
parsing_directives = false;
} else {
expected("statement or declaration");
consume();
parsing_directives = false;
}
}
if (m_state.var_scopes.size() == 1) {
scope.add_to_scope_node(program);
} else {
syntax_error("Unclosed lexical_environment");
}
program->source_range().end = position();
return program;
}
NonnullRefPtr<Declaration> Parser::parse_declaration()
{
auto rule_start = push_start();
switch (m_state.current_token.type()) {
case TokenType::Class:
return parse_class_declaration();
case TokenType::Function: {
auto declaration = parse_function_node<FunctionDeclaration>();
m_state.current_scope->function_declarations.append(declaration);
auto hoisting_target = m_state.current_scope->get_current_function_scope();
hoisting_target->hoisted_function_declarations.append({ declaration, *m_state.current_scope });
return declaration;
}
case TokenType::Let:
case TokenType::Const:
return parse_variable_declaration();
default:
expected("declaration");
consume();
return create_ast_node<ErrorDeclaration>({ m_state.current_token.filename(), rule_start.position(), position() });
}
}
NonnullRefPtr<Statement> Parser::parse_statement(AllowLabelledFunction allow_labelled_function)
{
auto rule_start = push_start();
auto type = m_state.current_token.type();
switch (type) {
case TokenType::CurlyOpen:
return parse_block_statement();
case TokenType::Return:
return parse_return_statement();
case TokenType::Var:
return parse_variable_declaration();
case TokenType::For:
return parse_for_statement();
case TokenType::If:
return parse_if_statement();
case TokenType::Throw:
return parse_throw_statement();
case TokenType::Try:
return parse_try_statement();
case TokenType::Break:
return parse_break_statement();
case TokenType::Continue:
return parse_continue_statement();
case TokenType::Switch:
return parse_switch_statement();
case TokenType::Do:
return parse_do_while_statement();
case TokenType::While:
return parse_while_statement();
case TokenType::With:
if (m_state.strict_mode)
syntax_error("'with' statement not allowed in strict mode");
return parse_with_statement();
case TokenType::Debugger:
return parse_debugger_statement();
case TokenType::Semicolon:
consume();
return create_ast_node<EmptyStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
case TokenType::Slash:
case TokenType::SlashEquals:
m_state.current_token = m_state.lexer.force_slash_as_regex();
[[fallthrough]];
default:
if (type == TokenType::EscapedKeyword
&& (m_state.strict_mode
|| (m_state.current_token.value() != "yield"sv && m_state.current_token.value() != "let"sv)))
syntax_error("Keyword must not contain escaped characters");
if (match_identifier_name()) {
auto result = try_parse_labelled_statement(allow_labelled_function);
if (!result.is_null())
return result.release_nonnull();
}
if (match_expression()) {
if (match(TokenType::Function) || match(TokenType::Class))
syntax_error(String::formatted("{} declaration not allowed in single-statement context", m_state.current_token.name()));
if (match(TokenType::Let) && next_token().type() == TokenType::BracketOpen)
syntax_error(String::formatted("let followed by [ is not allowed in single-statement context"));
auto expr = parse_expression(0);
consume_or_insert_semicolon();
return create_ast_node<ExpressionStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expr));
}
expected("statement");
consume();
return create_ast_node<ErrorStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
}
}
static constexpr AK::Array<StringView, 9> strict_reserved_words = { "implements", "interface", "let", "package", "private", "protected", "public", "static", "yield" };
static bool is_strict_reserved_word(StringView str)
{
return any_of(strict_reserved_words, [&str](StringView const& word) {
return word == str;
});
}
static bool is_simple_parameter_list(Vector<FunctionNode::Parameter> const& parameters)
{
return all_of(parameters, [](FunctionNode::Parameter const& parameter) {
return !parameter.is_rest && parameter.default_value.is_null() && parameter.binding.has<FlyString>();
});
}
RefPtr<FunctionExpression> Parser::try_parse_arrow_function_expression(bool expect_parens)
{
save_state();
auto rule_start = push_start();
ArmedScopeGuard state_rollback_guard = [&] {
load_state();
};
Vector<FunctionNode::Parameter> parameters;
i32 function_length = -1;
if (expect_parens) {
// We have parens around the function parameters and can re-use the same parsing
// logic used for regular functions: multiple parameters, default values, rest
// parameter, maybe a trailing comma. If we have a new syntax error afterwards we
// check if it's about a wrong token (something like duplicate parameter name must
// not abort), know parsing failed and rollback the parser state.
auto previous_syntax_errors = m_state.errors.size();
parameters = parse_formal_parameters(function_length, FunctionNodeParseOptions::IsArrowFunction);
if (m_state.errors.size() > previous_syntax_errors && m_state.errors[previous_syntax_errors].message.starts_with("Unexpected token"))
return nullptr;
if (!match(TokenType::ParenClose))
return nullptr;
consume();
} else {
// No parens - this must be an identifier followed by arrow. That's it.
if (!match_identifier() && !match(TokenType::Yield) && !match(TokenType::Await))
return nullptr;
auto token = consume_identifier_reference();
if (m_state.strict_mode && token.value().is_one_of("arguments"sv, "eval"sv))
syntax_error("BindingIdentifier may not be 'arguments' or 'eval' in strict mode");
parameters.append({ FlyString { token.value() }, {} });
}
// If there's a newline between the closing paren and arrow it's not a valid arrow function,
// ASI should kick in instead (it'll then fail with "Unexpected token Arrow")
if (m_state.current_token.trivia_contains_line_terminator())
return nullptr;
if (!match(TokenType::Arrow))
return nullptr;
consume();
if (function_length == -1)
function_length = parameters.size();
m_state.function_parameters.append(parameters);
auto old_labels_in_scope = move(m_state.labels_in_scope);
ScopeGuard guard([&]() {
m_state.labels_in_scope = move(old_labels_in_scope);
});
bool is_strict = false;
auto function_body_result = [&]() -> RefPtr<BlockStatement> {
TemporaryChange change(m_state.in_arrow_function_context, true);
if (match(TokenType::CurlyOpen)) {
// Parse a function body with statements
ScopePusher scope(*this, ScopePusher::Var, Scope::Function);
auto body = parse_block_statement(is_strict, !is_simple_parameter_list(parameters));
scope.add_to_scope_node(body);
return body;
}
if (match_expression()) {
// Parse a function body which returns a single expression
// FIXME: We synthesize a block with a return statement
// for arrow function bodies which are a single expression.
// Esprima generates a single "ArrowFunctionExpression"
// with a "body" property.
auto return_expression = parse_expression(2);
auto return_block = create_ast_node<BlockStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
return_block->append<ReturnStatement>({ m_filename, rule_start.position(), position() }, move(return_expression));
return return_block;
}
// Invalid arrow function body
return nullptr;
}();
m_state.function_parameters.take_last();
if (function_body_result.is_null())
return nullptr;
state_rollback_guard.disarm();
discard_saved_state();
auto body = function_body_result.release_nonnull();
if (is_strict) {
for (auto& parameter : parameters) {
parameter.binding.visit(
[&](FlyString const& name) {
check_identifier_name_for_assignment_validity(name, true);
},
[&](auto const&) {});
}
}
return create_ast_node<FunctionExpression>(
{ m_state.current_token.filename(), rule_start.position(), position() }, "", move(body),
move(parameters), function_length, FunctionKind::Regular, is_strict, true);
}
RefPtr<Statement> Parser::try_parse_labelled_statement(AllowLabelledFunction allow_function)
{
save_state();
auto rule_start = push_start();
ArmedScopeGuard state_rollback_guard = [&] {
load_state();
};
if (m_state.current_token.value() == "yield"sv && (m_state.strict_mode || m_state.in_generator_function_context)) {
syntax_error("'yield' label not allowed in this context");
return {};
}
auto identifier = consume_identifier_reference().value();
if (!match(TokenType::Colon))
return {};
consume(TokenType::Colon);
if (!match_statement())
return {};
if (match(TokenType::Function) && (allow_function == AllowLabelledFunction::No || m_state.strict_mode)) {
syntax_error("Not allowed to declare a function here");
return {};
}
if (m_state.labels_in_scope.contains(identifier))
syntax_error(String::formatted("Label '{}' has already been declared", identifier));
RefPtr<Statement> labelled_statement;
if (match(TokenType::Function)) {
m_state.labels_in_scope.set(identifier, false);
auto function_declaration = parse_function_node<FunctionDeclaration>();
m_state.current_scope->function_declarations.append(function_declaration);
auto hoisting_target = m_state.current_scope->get_current_function_scope();
hoisting_target->hoisted_function_declarations.append({ function_declaration, *m_state.current_scope });
if (function_declaration->kind() == FunctionKind::Generator)
syntax_error("Generator functions cannot be defined in labelled statements");
labelled_statement = move(function_declaration);
} else {
auto is_iteration_statement = match(TokenType::For) || match(TokenType::Do) || match(TokenType::While);
m_state.labels_in_scope.set(identifier, is_iteration_statement);
labelled_statement = parse_statement();
}
m_state.labels_in_scope.remove(identifier);
labelled_statement->set_label(identifier);
state_rollback_guard.disarm();
discard_saved_state();
return labelled_statement.release_nonnull();
}
RefPtr<MetaProperty> Parser::try_parse_new_target_expression()
{
save_state();
auto rule_start = push_start();
ArmedScopeGuard state_rollback_guard = [&] {
load_state();
};
consume(TokenType::New);
if (!match(TokenType::Period))
return {};
consume();
if (!match(TokenType::Identifier))
return {};
// The string 'target' cannot have escapes so we check original value.
if (consume().original_value() != "target"sv)
return {};
state_rollback_guard.disarm();
discard_saved_state();
return create_ast_node<MetaProperty>({ m_state.current_token.filename(), rule_start.position(), position() }, MetaProperty::Type::NewTarget);
}
NonnullRefPtr<ClassDeclaration> Parser::parse_class_declaration()
{
auto rule_start = push_start();
return create_ast_node<ClassDeclaration>({ m_state.current_token.filename(), rule_start.position(), position() }, parse_class_expression(true));
}
NonnullRefPtr<ClassExpression> Parser::parse_class_expression(bool expect_class_name)
{
auto rule_start = push_start();
// Classes are always in strict mode.
TemporaryChange strict_mode_rollback(m_state.strict_mode, true);
consume(TokenType::Class);
NonnullRefPtrVector<ClassMethod> methods;
NonnullRefPtrVector<ClassField> fields;
RefPtr<Expression> super_class;
RefPtr<FunctionExpression> constructor;
String class_name = expect_class_name || match_identifier() || match(TokenType::Yield) || match(TokenType::Await)
? consume_identifier_reference().value().to_string()
: "";
check_identifier_name_for_assignment_validity(class_name, true);
if (match(TokenType::Extends)) {
consume();
auto [expression, should_continue_parsing] = parse_primary_expression();
// Basically a (much) simplified parse_secondary_expression().
for (;;) {
if (match(TokenType::TemplateLiteralStart)) {
auto template_literal = parse_template_literal(true);
expression = create_ast_node<TaggedTemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression), move(template_literal));
continue;
}
if (match(TokenType::BracketOpen) || match(TokenType::Period) || match(TokenType::ParenOpen)) {
auto precedence = g_operator_precedence.get(m_state.current_token.type());
expression = parse_secondary_expression(move(expression), precedence);
continue;
}
break;
}
super_class = move(expression);
(void)should_continue_parsing;
}
consume(TokenType::CurlyOpen);
while (!done() && !match(TokenType::CurlyClose)) {
RefPtr<Expression> property_key;
bool is_static = false;
bool is_constructor = false;
bool is_generator = false;
auto method_kind = ClassMethod::Kind::Method;
if (match(TokenType::Semicolon)) {
consume();
continue;
}
if (match(TokenType::Asterisk)) {
consume();
is_generator = true;
}
StringView name;
if (match_property_key()) {
if (!is_generator && m_state.current_token.original_value() == "static"sv) {
if (match(TokenType::Identifier)) {
consume();
is_static = true;
if (match(TokenType::Asterisk)) {
consume();
is_generator = true;
}
}
}
if (match(TokenType::Identifier)) {
auto identifier_name = m_state.current_token.original_value();
if (identifier_name == "get"sv) {
method_kind = ClassMethod::Kind::Getter;
consume();
} else if (identifier_name == "set"sv) {
method_kind = ClassMethod::Kind::Setter;
consume();
}
}
if (match_property_key()) {
switch (m_state.current_token.type()) {
case TokenType::Identifier:
name = consume().value();
property_key = create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, name);
break;
case TokenType::StringLiteral: {
auto string_literal = parse_string_literal(consume());
name = string_literal->value();
property_key = move(string_literal);
break;
}
default:
property_key = parse_property_key();
break;
}
//https://tc39.es/ecma262/#sec-class-definitions-static-semantics-early-errors
// ClassElement : static MethodDefinition
// It is a Syntax Error if PropName of MethodDefinition is "prototype".
if (is_static && name == "prototype"sv)
syntax_error("Classes may not have a static property named 'prototype'");
} else if ((match(TokenType::ParenOpen) || match(TokenType::Equals)) && (is_static || method_kind != ClassMethod::Kind::Method)) {
switch (method_kind) {
case ClassMethod::Kind::Method:
VERIFY(is_static);
name = "static";
is_static = false;
break;
case ClassMethod::Kind::Getter:
name = "get";
method_kind = ClassMethod::Kind::Method;
break;
case ClassMethod::Kind::Setter:
name = "set";
method_kind = ClassMethod::Kind::Method;
break;
}
property_key = create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, name);
} else {
expected("property key");
}
// Constructor may be a StringLiteral or an Identifier.
if (!is_static && name == "constructor"sv) {
if (method_kind != ClassMethod::Kind::Method)
syntax_error("Class constructor may not be an accessor");
if (!constructor.is_null())
syntax_error("Classes may not have more than one constructor");
if (is_generator)
syntax_error("Class constructor may not be a generator");
is_constructor = true;
}
}
if (match(TokenType::ParenOpen)) {
u8 parse_options = FunctionNodeParseOptions::AllowSuperPropertyLookup;
if (!super_class.is_null() && !is_static && is_constructor)
parse_options |= FunctionNodeParseOptions::AllowSuperConstructorCall;
if (method_kind == ClassMethod::Kind::Getter)
parse_options |= FunctionNodeParseOptions::IsGetterFunction;
if (method_kind == ClassMethod::Kind::Setter)
parse_options |= FunctionNodeParseOptions::IsSetterFunction;
if (is_generator)
parse_options |= FunctionNodeParseOptions::IsGeneratorFunction;
auto function = parse_function_node<FunctionExpression>(parse_options);
if (is_constructor) {
constructor = move(function);
} else if (!property_key.is_null()) {
methods.append(create_ast_node<ClassMethod>({ m_state.current_token.filename(), rule_start.position(), position() }, property_key.release_nonnull(), move(function), method_kind, is_static));
} else {
syntax_error("No key for class method");
}
} else if (is_generator) {
expected("ParenOpen");
consume();
} else if (property_key.is_null()) {
expected("property key");
consume();
} else {
if (name == "constructor"sv)
syntax_error("Class cannot have field named 'constructor'");
RefPtr<Expression> initializer;
if (match(TokenType::Equals)) {
consume();
TemporaryChange super_property_access_rollback(m_state.allow_super_property_lookup, true);
TemporaryChange field_initializer_rollback(m_state.in_class_field_initializer, true);
initializer = parse_expression(2);
}
fields.append(create_ast_node<ClassField>({ m_state.current_token.filename(), rule_start.position(), position() }, property_key.release_nonnull(), move(initializer), is_static));
consume_or_insert_semicolon();
}
}
consume(TokenType::CurlyClose);
if (constructor.is_null()) {
auto constructor_body = create_ast_node<BlockStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
if (!super_class.is_null()) {
// Set constructor to the result of parsing the source text
// constructor(... args){ super (...args);}
auto super_call = create_ast_node<SuperCall>(
{ m_state.current_token.filename(), rule_start.position(), position() },
Vector { CallExpression::Argument { create_ast_node<Identifier>({ m_state.current_token.filename(), rule_start.position(), position() }, "args"), true } });
constructor_body->append(create_ast_node<ExpressionStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(super_call)));
constructor_body->add_variables(m_state.var_scopes.last());
constructor = create_ast_node<FunctionExpression>(
{ m_state.current_token.filename(), rule_start.position(), position() }, class_name, move(constructor_body),
Vector { FunctionNode::Parameter { FlyString { "args" }, nullptr, true } }, 0, FunctionKind::Regular, true);
} else {
constructor = create_ast_node<FunctionExpression>(
{ m_state.current_token.filename(), rule_start.position(), position() }, class_name, move(constructor_body),
Vector<FunctionNode::Parameter> {}, 0, FunctionKind::Regular, true);
}
}
return create_ast_node<ClassExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(class_name), move(constructor), move(super_class), move(methods), move(fields));
}
Parser::PrimaryExpressionParseResult Parser::parse_primary_expression()
{
auto rule_start = push_start();
if (match_unary_prefixed_expression())
return { parse_unary_prefixed_expression() };
switch (m_state.current_token.type()) {
case TokenType::ParenOpen: {
auto paren_position = position();
consume(TokenType::ParenOpen);
if ((match(TokenType::ParenClose) || match_identifier() || match(TokenType::TripleDot) || match(TokenType::CurlyOpen) || match(TokenType::BracketOpen))
&& !try_parse_arrow_function_expression_failed_at_position(paren_position)) {
auto arrow_function_result = try_parse_arrow_function_expression(true);
if (!arrow_function_result.is_null())
return { arrow_function_result.release_nonnull(), false };
set_try_parse_arrow_function_expression_failed_at_position(paren_position, true);
}
auto expression = parse_expression(0);
consume(TokenType::ParenClose);
if (is<FunctionExpression>(*expression)) {
auto& function = static_cast<FunctionExpression&>(*expression);
function.set_cannot_auto_rename();
if (function.kind() == FunctionKind::Generator && function.name() == "yield"sv)
syntax_error("function is not allowed to be called 'yield' in this context", function.source_range().start);
}
return { move(expression) };
}
case TokenType::This:
consume();
return { create_ast_node<ThisExpression>({ m_state.current_token.filename(), rule_start.position(), position() }) };
case TokenType::Class:
return { parse_class_expression(false) };
case TokenType::Super:
consume();
if (!m_state.allow_super_property_lookup)
syntax_error("'super' keyword unexpected here");
return { create_ast_node<SuperExpression>({ m_state.current_token.filename(), rule_start.position(), position() }) };
case TokenType::EscapedKeyword:
if (m_state.strict_mode || (m_state.current_token.value() != "let"sv && (m_state.in_generator_function_context || m_state.current_token.value() != "yield"sv)))
syntax_error("Keyword must not contain escaped characters");
[[fallthrough]];
case TokenType::Identifier: {
read_as_identifier:;
if (!try_parse_arrow_function_expression_failed_at_position(position())) {
auto arrow_function_result = try_parse_arrow_function_expression(false);
if (!arrow_function_result.is_null())
return { arrow_function_result.release_nonnull(), false };
set_try_parse_arrow_function_expression_failed_at_position(position(), true);
}
auto string = m_state.current_token.value();
// This could be 'eval' or 'arguments' and thus needs a custom check (`eval[1] = true`)
if (m_state.strict_mode && (string == "let" || is_strict_reserved_word(string)))
syntax_error(String::formatted("Identifier must not be a reserved word in strict mode ('{}')", string));
return { parse_identifier() };
}
case TokenType::NumericLiteral:
return { create_ast_node<NumericLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume_and_validate_numeric_literal().double_value()) };
case TokenType::BigIntLiteral:
return { create_ast_node<BigIntLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().value()) };
case TokenType::BoolLiteral:
return { create_ast_node<BooleanLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().bool_value()) };
case TokenType::StringLiteral:
return { parse_string_literal(consume()) };
case TokenType::NullLiteral:
consume();
return { create_ast_node<NullLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }) };
case TokenType::CurlyOpen:
return { parse_object_expression() };
case TokenType::Function:
return { parse_function_node<FunctionExpression>() };
case TokenType::BracketOpen:
return { parse_array_expression() };
case TokenType::RegexLiteral:
return { parse_regexp_literal() };
case TokenType::TemplateLiteralStart:
return { parse_template_literal(false) };
case TokenType::New: {
auto new_start = position();
auto new_target_result = try_parse_new_target_expression();
if (!new_target_result.is_null()) {
if (!m_state.in_function_context)
syntax_error("'new.target' not allowed outside of a function", new_start);
return { new_target_result.release_nonnull() };
}
return { parse_new_expression() };
}
case TokenType::Yield:
if (!m_state.in_generator_function_context)
goto read_as_identifier;
return { parse_yield_expression(), false };
default:
if (match_identifier_name())
goto read_as_identifier;
expected("primary expression");
consume();
return { create_ast_node<ErrorExpression>({ m_state.current_token.filename(), rule_start.position(), position() }) };
}
}
NonnullRefPtr<RegExpLiteral> Parser::parse_regexp_literal()
{
auto rule_start = push_start();
auto pattern = consume().value();
// Remove leading and trailing slash.
pattern = pattern.substring_view(1, pattern.length() - 2);
auto flags = String::empty();
auto parsed_flags = RegExpObject::default_flags;
if (match(TokenType::RegexFlags)) {
auto flags_start = position();
flags = consume().value();
auto parsed_flags_or_error = regex_flags_from_string(flags);
if (parsed_flags_or_error.is_error())
syntax_error(parsed_flags_or_error.release_error(), flags_start);
else
parsed_flags = parsed_flags_or_error.release_value();
}
auto parsed_pattern = parse_regex_pattern(pattern, parsed_flags.has_flag_set(ECMAScriptFlags::Unicode));
auto parsed_regex = Regex<ECMA262>::parse_pattern(parsed_pattern, parsed_flags);
if (parsed_regex.error != regex::Error::NoError)
syntax_error(String::formatted("RegExp compile error: {}", Regex<ECMA262>(parsed_regex, parsed_pattern, parsed_flags).error_string()), rule_start.position());
SourceRange range { m_state.current_token.filename(), rule_start.position(), position() };
return create_ast_node<RegExpLiteral>(move(range), move(parsed_regex), move(parsed_pattern), move(parsed_flags), pattern.to_string(), move(flags));
}
NonnullRefPtr<Expression> Parser::parse_unary_prefixed_expression()
{
auto rule_start = push_start();
auto precedence = g_operator_precedence.get(m_state.current_token.type());
auto associativity = operator_associativity(m_state.current_token.type());
switch (m_state.current_token.type()) {
case TokenType::PlusPlus: {
consume();
auto rhs_start = position();
auto rhs = parse_expression(precedence, associativity);
// FIXME: Apparently for functions this should also not be enforced on a parser level,
// other engines throw ReferenceError for ++foo()
if (!is<Identifier>(*rhs) && !is<MemberExpression>(*rhs))
syntax_error(String::formatted("Right-hand side of prefix increment operator must be identifier or member expression, got {}", rhs->class_name()), rhs_start);
if (m_state.strict_mode && is<Identifier>(*rhs)) {
auto& identifier = static_cast<Identifier&>(*rhs);
auto& name = identifier.string();
check_identifier_name_for_assignment_validity(name);
}
return create_ast_node<UpdateExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UpdateOp::Increment, move(rhs), true);
}
case TokenType::MinusMinus: {
consume();
auto rhs_start = position();
auto rhs = parse_expression(precedence, associativity);
// FIXME: Apparently for functions this should also not be enforced on a parser level,
// other engines throw ReferenceError for --foo()
if (!is<Identifier>(*rhs) && !is<MemberExpression>(*rhs))
syntax_error(String::formatted("Right-hand side of prefix decrement operator must be identifier or member expression, got {}", rhs->class_name()), rhs_start);
if (m_state.strict_mode && is<Identifier>(*rhs)) {
auto& identifier = static_cast<Identifier&>(*rhs);
auto& name = identifier.string();
check_identifier_name_for_assignment_validity(name);
}
return create_ast_node<UpdateExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UpdateOp::Decrement, move(rhs), true);
}
case TokenType::ExclamationMark:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Not, parse_expression(precedence, associativity));
case TokenType::Tilde:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::BitwiseNot, parse_expression(precedence, associativity));
case TokenType::Plus:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Plus, parse_expression(precedence, associativity));
case TokenType::Minus:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Minus, parse_expression(precedence, associativity));
case TokenType::Typeof:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Typeof, parse_expression(precedence, associativity));
case TokenType::Void:
consume();
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Void, parse_expression(precedence, associativity));
case TokenType::Delete: {
consume();
auto rhs_start = position();
auto rhs = parse_expression(precedence, associativity);
if (is<Identifier>(*rhs) && m_state.strict_mode) {
syntax_error("Delete of an unqualified identifier in strict mode.", rhs_start);
}
return create_ast_node<UnaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UnaryOp::Delete, move(rhs));
}
default:
expected("primary expression");
consume();
return create_ast_node<ErrorExpression>({ m_state.current_token.filename(), rule_start.position(), position() });
}
}
NonnullRefPtr<Expression> Parser::parse_property_key()
{
auto rule_start = push_start();
if (match(TokenType::StringLiteral)) {
return parse_string_literal(consume());
} else if (match(TokenType::NumericLiteral)) {
return create_ast_node<NumericLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().double_value());
} else if (match(TokenType::BigIntLiteral)) {
return create_ast_node<BigIntLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().value());
} else if (match(TokenType::BracketOpen)) {
consume(TokenType::BracketOpen);
auto result = parse_expression(2);
consume(TokenType::BracketClose);
return result;
} else {
if (!match_identifier_name())
expected("IdentifierName");
return create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().value());
}
}
NonnullRefPtr<ObjectExpression> Parser::parse_object_expression()
{
auto rule_start = push_start();
consume(TokenType::CurlyOpen);
NonnullRefPtrVector<ObjectProperty> properties;
ObjectProperty::Type property_type;
Optional<SourceRange> invalid_object_literal_property_range;
auto skip_to_next_property = [&] {
while (!done() && !match(TokenType::Comma) && !match(TokenType::CurlyOpen))
consume();
};
// It is a Syntax Error if PropertyNameList of PropertyDefinitionList contains any duplicate
// entries for "__proto__" and at least two of those entries were obtained from productions of
// the form PropertyDefinition : PropertyName : AssignmentExpression .
bool has_direct_proto_property = false;
while (!done() && !match(TokenType::CurlyClose)) {
property_type = ObjectProperty::Type::KeyValue;
RefPtr<Expression> property_name;
RefPtr<Expression> property_value;
FunctionKind function_kind { FunctionKind::Regular };
if (match(TokenType::TripleDot)) {
consume();
property_name = parse_expression(4);
properties.append(create_ast_node<ObjectProperty>({ m_state.current_token.filename(), rule_start.position(), position() }, *property_name, nullptr, ObjectProperty::Type::Spread, false));
if (!match(TokenType::Comma))
break;
consume(TokenType::Comma);
continue;
}
auto type = m_state.current_token.type();
if (match(TokenType::Asterisk)) {
consume();
property_type = ObjectProperty::Type::KeyValue;
property_name = parse_property_key();
function_kind = FunctionKind ::Generator;
} else if (match_identifier()) {
auto identifier = consume();
if (identifier.original_value() == "get"sv && match_property_key()) {
property_type = ObjectProperty::Type::Getter;
property_name = parse_property_key();
} else if (identifier.original_value() == "set"sv && match_property_key()) {
property_type = ObjectProperty::Type::Setter;
property_name = parse_property_key();
} else {
property_name = create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, identifier.value());
property_value = create_ast_node<Identifier>({ m_state.current_token.filename(), rule_start.position(), position() }, identifier.value());
}
} else {
property_name = parse_property_key();
}
bool is_proto = (type == TokenType::StringLiteral || type == TokenType::Identifier) && is<StringLiteral>(*property_name) && static_cast<StringLiteral const&>(*property_name).value() == "__proto__";
if (property_type == ObjectProperty::Type::Getter || property_type == ObjectProperty::Type::Setter) {
if (!match(TokenType::ParenOpen)) {
expected("'(' for object getter or setter property");
skip_to_next_property();
continue;
}
}
if (match(TokenType::Equals)) {
// Not a valid object literal, but a valid assignment target
consume();
// Parse the expression and throw it away
auto expression = parse_expression(2);
if (!invalid_object_literal_property_range.has_value())
invalid_object_literal_property_range = expression->source_range();
} else if (match(TokenType::ParenOpen)) {
VERIFY(property_name);
u8 parse_options = FunctionNodeParseOptions::AllowSuperPropertyLookup;
if (property_type == ObjectProperty::Type::Getter)
parse_options |= FunctionNodeParseOptions::IsGetterFunction;
if (property_type == ObjectProperty::Type::Setter)
parse_options |= FunctionNodeParseOptions::IsSetterFunction;
if (function_kind == FunctionKind::Generator)
parse_options |= FunctionNodeParseOptions::IsGeneratorFunction;
auto function = parse_function_node<FunctionExpression>(parse_options);
properties.append(create_ast_node<ObjectProperty>({ m_state.current_token.filename(), rule_start.position(), position() }, *property_name, function, property_type, true));
} else if (match(TokenType::Colon)) {
if (!property_name) {
expected("a property name");
skip_to_next_property();
continue;
}
consume();
if (is_proto) {
if (has_direct_proto_property)
syntax_error("Property name '__proto__' must not appear more than once in object literal");
has_direct_proto_property = true;
}
properties.append(create_ast_node<ObjectProperty>({ m_state.current_token.filename(), rule_start.position(), position() }, *property_name, parse_expression(2), property_type, false));
} else if (property_name && property_value) {
properties.append(create_ast_node<ObjectProperty>({ m_state.current_token.filename(), rule_start.position(), position() }, *property_name, *property_value, property_type, false));
} else {
expected("a property");
skip_to_next_property();
continue;
}
if (!match(TokenType::Comma))
break;
consume(TokenType::Comma);
}
consume(TokenType::CurlyClose);
return create_ast_node<ObjectExpression>(
{ m_state.current_token.filename(), rule_start.position(), position() },
move(properties),
move(invalid_object_literal_property_range));
}
NonnullRefPtr<ArrayExpression> Parser::parse_array_expression()
{
auto rule_start = push_start();
consume(TokenType::BracketOpen);
Vector<RefPtr<Expression>> elements;
while (match_expression() || match(TokenType::TripleDot) || match(TokenType::Comma)) {
RefPtr<Expression> expression;
if (match(TokenType::TripleDot)) {
consume(TokenType::TripleDot);
expression = create_ast_node<SpreadExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, parse_expression(2));
} else if (match_expression()) {
expression = parse_expression(2);
}
elements.append(expression);
if (!match(TokenType::Comma))
break;
consume(TokenType::Comma);
}
consume(TokenType::BracketClose);
return create_ast_node<ArrayExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(elements));
}
NonnullRefPtr<StringLiteral> Parser::parse_string_literal(const Token& token, bool in_template_literal)
{
auto rule_start = push_start();
auto status = Token::StringValueStatus::Ok;
auto string = token.string_value(status);
if (status != Token::StringValueStatus::Ok) {
String message;
if (status == Token::StringValueStatus::LegacyOctalEscapeSequence) {
m_state.string_legacy_octal_escape_sequence_in_scope = true;
if (in_template_literal)
message = "Octal escape sequence not allowed in template literal";
else if (m_state.strict_mode)
message = "Octal escape sequence in string literal not allowed in strict mode";
} else if (status == Token::StringValueStatus::MalformedHexEscape || status == Token::StringValueStatus::MalformedUnicodeEscape) {
auto type = status == Token::StringValueStatus::MalformedUnicodeEscape ? "unicode" : "hexadecimal";
message = String::formatted("Malformed {} escape sequence", type);
} else if (status == Token::StringValueStatus::UnicodeEscapeOverflow) {
message = "Unicode code_point must not be greater than 0x10ffff in escape sequence";
} else {
VERIFY_NOT_REACHED();
}
if (!message.is_empty())
syntax_error(message, Position { token.line_number(), token.line_column() });
}
auto is_use_strict_directive = !in_template_literal && (token.value() == "'use strict'" || token.value() == "\"use strict\"");
return create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, string, is_use_strict_directive);
}
NonnullRefPtr<TemplateLiteral> Parser::parse_template_literal(bool is_tagged)
{
auto rule_start = push_start();
consume(TokenType::TemplateLiteralStart);
NonnullRefPtrVector<Expression> expressions;
NonnullRefPtrVector<Expression> raw_strings;
auto append_empty_string = [this, &rule_start, &expressions, &raw_strings, is_tagged]() {
auto string_literal = create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, "");
expressions.append(string_literal);
if (is_tagged)
raw_strings.append(string_literal);
};
if (!match(TokenType::TemplateLiteralString))
append_empty_string();
while (!done() && !match(TokenType::TemplateLiteralEnd) && !match(TokenType::UnterminatedTemplateLiteral)) {
if (match(TokenType::TemplateLiteralString)) {
auto token = consume();
expressions.append(parse_string_literal(token, true));
if (is_tagged)
raw_strings.append(create_ast_node<StringLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, token.value()));
} else if (match(TokenType::TemplateLiteralExprStart)) {
consume(TokenType::TemplateLiteralExprStart);
if (match(TokenType::TemplateLiteralExprEnd)) {
syntax_error("Empty template literal expression block");
return create_ast_node<TemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, expressions);
}
expressions.append(parse_expression(0));
if (match(TokenType::UnterminatedTemplateLiteral)) {
syntax_error("Unterminated template literal");
return create_ast_node<TemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, expressions);
}
consume(TokenType::TemplateLiteralExprEnd);
if (!match(TokenType::TemplateLiteralString))
append_empty_string();
} else {
expected("Template literal string or expression");
break;
}
}
if (match(TokenType::UnterminatedTemplateLiteral)) {
syntax_error("Unterminated template literal");
} else {
consume(TokenType::TemplateLiteralEnd);
}
if (is_tagged)
return create_ast_node<TemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, expressions, raw_strings);
return create_ast_node<TemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, expressions);
}
NonnullRefPtr<Expression> Parser::parse_expression(int min_precedence, Associativity associativity, const Vector<TokenType>& forbidden)
{
auto rule_start = push_start();
auto [expression, should_continue_parsing] = parse_primary_expression();
auto check_for_invalid_object_property = [&](auto& expression) {
if (is<ObjectExpression>(*expression)) {
if (auto range = static_cast<ObjectExpression&>(*expression).invalid_property_range(); range.has_value())
syntax_error("Invalid property in object literal", range->start);
}
};
while (match(TokenType::TemplateLiteralStart)) {
auto template_literal = parse_template_literal(true);
expression = create_ast_node<TaggedTemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression), move(template_literal));
}
if (should_continue_parsing) {
while (match_secondary_expression(forbidden)) {
int new_precedence = g_operator_precedence.get(m_state.current_token.type());
if (new_precedence < min_precedence)
break;
if (new_precedence == min_precedence && associativity == Associativity::Left)
break;
check_for_invalid_object_property(expression);
Associativity new_associativity = operator_associativity(m_state.current_token.type());
expression = parse_secondary_expression(move(expression), new_precedence, new_associativity);
while (match(TokenType::TemplateLiteralStart) && !is<UpdateExpression>(*expression)) {
auto template_literal = parse_template_literal(true);
expression = create_ast_node<TaggedTemplateLiteral>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression), move(template_literal));
}
}
}
if (is<SuperExpression>(*expression))
syntax_error("'super' keyword unexpected here");
check_for_invalid_object_property(expression);
if (match(TokenType::Comma) && min_precedence <= 1) {
NonnullRefPtrVector<Expression> expressions;
expressions.append(expression);
while (match(TokenType::Comma)) {
consume();
expressions.append(parse_expression(2));
}
expression = create_ast_node<SequenceExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expressions));
}
return expression;
}
NonnullRefPtr<Expression> Parser::parse_secondary_expression(NonnullRefPtr<Expression> lhs, int min_precedence, Associativity associativity)
{
auto rule_start = push_start();
switch (m_state.current_token.type()) {
case TokenType::Plus:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Addition, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::PlusEquals:
return parse_assignment_expression(AssignmentOp::AdditionAssignment, move(lhs), min_precedence, associativity);
case TokenType::Minus:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Subtraction, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::MinusEquals:
return parse_assignment_expression(AssignmentOp::SubtractionAssignment, move(lhs), min_precedence, associativity);
case TokenType::Asterisk:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Multiplication, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::AsteriskEquals:
return parse_assignment_expression(AssignmentOp::MultiplicationAssignment, move(lhs), min_precedence, associativity);
case TokenType::Slash:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Division, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::SlashEquals:
return parse_assignment_expression(AssignmentOp::DivisionAssignment, move(lhs), min_precedence, associativity);
case TokenType::Percent:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Modulo, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::PercentEquals:
return parse_assignment_expression(AssignmentOp::ModuloAssignment, move(lhs), min_precedence, associativity);
case TokenType::DoubleAsterisk:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::Exponentiation, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::DoubleAsteriskEquals:
return parse_assignment_expression(AssignmentOp::ExponentiationAssignment, move(lhs), min_precedence, associativity);
case TokenType::GreaterThan:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::GreaterThan, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::GreaterThanEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::GreaterThanEquals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::LessThan:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::LessThan, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::LessThanEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::LessThanEquals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::EqualsEqualsEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::TypedEquals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::ExclamationMarkEqualsEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::TypedInequals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::EqualsEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::AbstractEquals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::ExclamationMarkEquals:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::AbstractInequals, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::In:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::In, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::Instanceof:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::InstanceOf, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::Ampersand:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::BitwiseAnd, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::AmpersandEquals:
return parse_assignment_expression(AssignmentOp::BitwiseAndAssignment, move(lhs), min_precedence, associativity);
case TokenType::Pipe:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::BitwiseOr, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::PipeEquals:
return parse_assignment_expression(AssignmentOp::BitwiseOrAssignment, move(lhs), min_precedence, associativity);
case TokenType::Caret:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::BitwiseXor, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::CaretEquals:
return parse_assignment_expression(AssignmentOp::BitwiseXorAssignment, move(lhs), min_precedence, associativity);
case TokenType::ShiftLeft:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::LeftShift, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::ShiftLeftEquals:
return parse_assignment_expression(AssignmentOp::LeftShiftAssignment, move(lhs), min_precedence, associativity);
case TokenType::ShiftRight:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::RightShift, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::ShiftRightEquals:
return parse_assignment_expression(AssignmentOp::RightShiftAssignment, move(lhs), min_precedence, associativity);
case TokenType::UnsignedShiftRight:
consume();
return create_ast_node<BinaryExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, BinaryOp::UnsignedRightShift, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::UnsignedShiftRightEquals:
return parse_assignment_expression(AssignmentOp::UnsignedRightShiftAssignment, move(lhs), min_precedence, associativity);
case TokenType::ParenOpen:
return parse_call_expression(move(lhs));
case TokenType::Equals:
return parse_assignment_expression(AssignmentOp::Assignment, move(lhs), min_precedence, associativity);
case TokenType::Period:
consume();
if (!match_identifier_name())
expected("IdentifierName");
return create_ast_node<MemberExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(lhs), create_ast_node<Identifier>({ m_state.current_token.filename(), rule_start.position(), position() }, consume().value()));
case TokenType::BracketOpen: {
consume(TokenType::BracketOpen);
auto expression = create_ast_node<MemberExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(lhs), parse_expression(0), true);
consume(TokenType::BracketClose);
return expression;
}
case TokenType::PlusPlus:
// FIXME: Apparently for functions this should also not be enforced on a parser level,
// other engines throw ReferenceError for foo()++
if (!is<Identifier>(*lhs) && !is<MemberExpression>(*lhs))
syntax_error(String::formatted("Left-hand side of postfix increment operator must be identifier or member expression, got {}", lhs->class_name()));
if (m_state.strict_mode && is<Identifier>(*lhs)) {
auto& identifier = static_cast<Identifier&>(*lhs);
auto& name = identifier.string();
check_identifier_name_for_assignment_validity(name);
}
consume();
return create_ast_node<UpdateExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UpdateOp::Increment, move(lhs));
case TokenType::MinusMinus:
// FIXME: Apparently for functions this should also not be enforced on a parser level,
// other engines throw ReferenceError for foo()--
if (!is<Identifier>(*lhs) && !is<MemberExpression>(*lhs))
syntax_error(String::formatted("Left-hand side of postfix increment operator must be identifier or member expression, got {}", lhs->class_name()));
if (m_state.strict_mode && is<Identifier>(*lhs)) {
auto& identifier = static_cast<Identifier&>(*lhs);
auto& name = identifier.string();
check_identifier_name_for_assignment_validity(name);
}
consume();
return create_ast_node<UpdateExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, UpdateOp::Decrement, move(lhs));
case TokenType::DoubleAmpersand:
consume();
return create_ast_node<LogicalExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, LogicalOp::And, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::DoubleAmpersandEquals:
return parse_assignment_expression(AssignmentOp::AndAssignment, move(lhs), min_precedence, associativity);
case TokenType::DoublePipe:
consume();
return create_ast_node<LogicalExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, LogicalOp::Or, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::DoublePipeEquals:
return parse_assignment_expression(AssignmentOp::OrAssignment, move(lhs), min_precedence, associativity);
case TokenType::DoubleQuestionMark:
consume();
return create_ast_node<LogicalExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, LogicalOp::NullishCoalescing, move(lhs), parse_expression(min_precedence, associativity));
case TokenType::DoubleQuestionMarkEquals:
return parse_assignment_expression(AssignmentOp::NullishAssignment, move(lhs), min_precedence, associativity);
case TokenType::QuestionMark:
return parse_conditional_expression(move(lhs));
default:
expected("secondary expression");
consume();
return create_ast_node<ErrorExpression>({ m_state.current_token.filename(), rule_start.position(), position() });
}
}
NonnullRefPtr<AssignmentExpression> Parser::parse_assignment_expression(AssignmentOp assignment_op, NonnullRefPtr<Expression> lhs, int min_precedence, Associativity associativity)
{
auto rule_start = push_start();
VERIFY(match(TokenType::Equals)
|| match(TokenType::PlusEquals)
|| match(TokenType::MinusEquals)
|| match(TokenType::AsteriskEquals)
|| match(TokenType::SlashEquals)
|| match(TokenType::PercentEquals)
|| match(TokenType::DoubleAsteriskEquals)
|| match(TokenType::AmpersandEquals)
|| match(TokenType::PipeEquals)
|| match(TokenType::CaretEquals)
|| match(TokenType::ShiftLeftEquals)
|| match(TokenType::ShiftRightEquals)
|| match(TokenType::UnsignedShiftRightEquals)
|| match(TokenType::DoubleAmpersandEquals)
|| match(TokenType::DoublePipeEquals)
|| match(TokenType::DoubleQuestionMarkEquals));
consume();
if (assignment_op == AssignmentOp::Assignment) {
auto synthesize_binding_pattern = [this](Expression const& expression) -> RefPtr<BindingPattern> {
// Clear any syntax error that has occurred in the range that 'expression' spans.
m_state.errors.remove_all_matching([range = expression.source_range()](auto const& error) {
return error.position.has_value() && range.contains(*error.position);
});
// Make a parser and parse the source for this expression as a binding pattern.
auto source = m_state.lexer.source().substring_view(expression.source_range().start.offset - 2, expression.source_range().end.offset - expression.source_range().start.offset);
Lexer lexer { source, m_state.lexer.filename(), expression.source_range().start.line, expression.source_range().start.column };
Parser parser { lexer };
parser.m_state.strict_mode = m_state.strict_mode;
parser.m_state.allow_super_property_lookup = m_state.allow_super_property_lookup;
parser.m_state.allow_super_constructor_call = m_state.allow_super_constructor_call;
parser.m_state.in_function_context = m_state.in_function_context;
parser.m_state.in_formal_parameter_context = m_state.in_formal_parameter_context;
parser.m_state.in_generator_function_context = m_state.in_generator_function_context;
parser.m_state.in_arrow_function_context = m_state.in_arrow_function_context;
parser.m_state.in_break_context = m_state.in_break_context;
parser.m_state.in_continue_context = m_state.in_continue_context;
parser.m_state.string_legacy_octal_escape_sequence_in_scope = m_state.string_legacy_octal_escape_sequence_in_scope;
parser.m_state.in_class_field_initializer = m_state.in_class_field_initializer;
auto result = parser.parse_binding_pattern();
if (parser.has_errors())
m_state.errors.extend(parser.errors());
return result;
};
if (is<ArrayExpression>(*lhs) || is<ObjectExpression>(*lhs)) {
auto binding_pattern = synthesize_binding_pattern(*lhs);
if (binding_pattern) {
auto rhs = parse_expression(min_precedence, associativity);
return create_ast_node<AssignmentExpression>(
{ m_state.current_token.filename(), rule_start.position(), position() },
assignment_op,
binding_pattern.release_nonnull(),
move(rhs));
}
}
}
if (!is<Identifier>(*lhs) && !is<MemberExpression>(*lhs) && !is<CallExpression>(*lhs)) {
syntax_error("Invalid left-hand side in assignment");
} else if (m_state.strict_mode && is<Identifier>(*lhs)) {
auto name = static_cast<const Identifier&>(*lhs).string();
check_identifier_name_for_assignment_validity(name);
} else if (m_state.strict_mode && is<CallExpression>(*lhs)) {
syntax_error("Cannot assign to function call");
}
auto rhs = parse_expression(min_precedence, associativity);
if (assignment_op == AssignmentOp::Assignment && is<FunctionExpression>(*rhs)) {
auto ident = lhs;
if (is<MemberExpression>(*lhs)) {
ident = static_cast<MemberExpression&>(*lhs).property();
}
if (is<Identifier>(*ident))
static_cast<FunctionExpression&>(*rhs).set_name_if_possible(static_cast<Identifier&>(*ident).string());
}
return create_ast_node<AssignmentExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, assignment_op, move(lhs), move(rhs));
}
NonnullRefPtr<Identifier> Parser::parse_identifier()
{
auto identifier_start = position();
auto token = consume_identifier();
if (m_state.in_class_field_initializer && token.value() == "arguments"sv)
syntax_error("'arguments' is not allowed in class field initializer");
return create_ast_node<Identifier>(
{ m_state.current_token.filename(), identifier_start, position() },
token.value());
}
NonnullRefPtr<Expression> Parser::parse_call_expression(NonnullRefPtr<Expression> lhs)
{
auto rule_start = push_start();
if (!m_state.allow_super_constructor_call && is<SuperExpression>(*lhs))
syntax_error("'super' keyword unexpected here");
consume(TokenType::ParenOpen);
Vector<CallExpression::Argument> arguments;
while (match_expression() || match(TokenType::TripleDot)) {
if (match(TokenType::TripleDot)) {
consume();
arguments.append({ parse_expression(2), true });
} else {
arguments.append({ parse_expression(2), false });
}
if (!match(TokenType::Comma))
break;
consume();
}
consume(TokenType::ParenClose);
if (is<SuperExpression>(*lhs))
return create_ast_node<SuperCall>({ m_state.current_token.filename(), rule_start.position(), position() }, move(arguments));
return create_ast_node<CallExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(lhs), move(arguments));
}
NonnullRefPtr<NewExpression> Parser::parse_new_expression()
{
auto rule_start = push_start();
consume(TokenType::New);
auto callee = parse_expression(g_operator_precedence.get(TokenType::New), Associativity::Right, { TokenType::ParenOpen });
Vector<CallExpression::Argument> arguments;
if (match(TokenType::ParenOpen)) {
consume(TokenType::ParenOpen);
while (match_expression() || match(TokenType::TripleDot)) {
if (match(TokenType::TripleDot)) {
consume();
arguments.append({ parse_expression(2), true });
} else {
arguments.append({ parse_expression(2), false });
}
if (!match(TokenType::Comma))
break;
consume();
}
consume(TokenType::ParenClose);
}
return create_ast_node<NewExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(callee), move(arguments));
}
NonnullRefPtr<YieldExpression> Parser::parse_yield_expression()
{
auto rule_start = push_start();
if (m_state.in_formal_parameter_context)
syntax_error("'Yield' expression is not allowed in formal parameters of generator function");
consume(TokenType::Yield);
RefPtr<Expression> argument;
bool yield_from = false;
if (!m_state.current_token.trivia_contains_line_terminator()) {
if (match(TokenType::Asterisk)) {
consume();
yield_from = true;
}
if (yield_from || match_expression() || match(TokenType::Class))
argument = parse_expression(0);
}
return create_ast_node<YieldExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(argument), yield_from);
}
NonnullRefPtr<ReturnStatement> Parser::parse_return_statement()
{
auto rule_start = push_start();
if (!m_state.in_function_context && !m_state.in_arrow_function_context)
syntax_error("'return' not allowed outside of a function");
consume(TokenType::Return);
// Automatic semicolon insertion: terminate statement when return is followed by newline
if (m_state.current_token.trivia_contains_line_terminator())
return create_ast_node<ReturnStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, nullptr);
if (match_expression()) {
auto expression = parse_expression(0);
consume_or_insert_semicolon();
return create_ast_node<ReturnStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression));
}
consume_or_insert_semicolon();
return create_ast_node<ReturnStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, nullptr);
}
NonnullRefPtr<BlockStatement> Parser::parse_block_statement()
{
auto rule_start = push_start();
bool dummy = false;
return parse_block_statement(dummy);
}
NonnullRefPtr<BlockStatement> Parser::parse_block_statement(bool& is_strict, bool function_with_non_simple_parameter_list)
{
auto rule_start = push_start();
ScopePusher scope(*this, ScopePusher::Let, Parser::Scope::Block);
auto block = create_ast_node<BlockStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
consume(TokenType::CurlyOpen);
bool initial_strict_mode_state = m_state.strict_mode;
if (initial_strict_mode_state)
is_strict = true;
bool parsing_directives = true;
while (!done() && !match(TokenType::CurlyClose)) {
if (match_declaration()) {
block->append(parse_declaration());
parsing_directives = false;
} else if (match_statement()) {
auto statement = parse_statement(AllowLabelledFunction::Yes);
block->append(statement);
if (statement_is_use_strict_directive(statement)) {
if (parsing_directives) {
if (!initial_strict_mode_state) {
is_strict = true;
m_state.strict_mode = true;
}
}
if (m_state.string_legacy_octal_escape_sequence_in_scope)
syntax_error("Octal escape sequence in string literal not allowed in strict mode");
if (function_with_non_simple_parameter_list) {
syntax_error("Illegal 'use strict' directive in function with non-simple parameter list", statement->source_range().start);
}
}
if (parsing_directives && is<ExpressionStatement>(*statement)) {
auto& expression_statement = static_cast<ExpressionStatement&>(*statement);
auto& expression = expression_statement.expression();
parsing_directives = is<StringLiteral>(expression);
} else {
parsing_directives = false;
}
} else {
expected("statement or declaration");
consume();
parsing_directives = false;
}
}
m_state.strict_mode = initial_strict_mode_state;
m_state.string_legacy_octal_escape_sequence_in_scope = false;
consume(TokenType::CurlyClose);
scope.add_to_scope_node(block);
return block;
}
template<typename FunctionNodeType>
NonnullRefPtr<FunctionNodeType> Parser::parse_function_node(u8 parse_options)
{
auto rule_start = push_start();
VERIFY(!(parse_options & FunctionNodeParseOptions::IsGetterFunction && parse_options & FunctionNodeParseOptions::IsSetterFunction));
TemporaryChange super_property_access_rollback(m_state.allow_super_property_lookup, !!(parse_options & FunctionNodeParseOptions::AllowSuperPropertyLookup));
TemporaryChange super_constructor_call_rollback(m_state.allow_super_constructor_call, !!(parse_options & FunctionNodeParseOptions::AllowSuperConstructorCall));
TemporaryChange break_context_rollback(m_state.in_break_context, false);
TemporaryChange continue_context_rollback(m_state.in_continue_context, false);
TemporaryChange class_field_initializer_rollback(m_state.in_class_field_initializer, false);
ScopePusher scope(*this, ScopePusher::Var, Parser::Scope::Function);
constexpr auto is_function_expression = IsSame<FunctionNodeType, FunctionExpression>;
auto is_generator = (parse_options & FunctionNodeParseOptions::IsGeneratorFunction) != 0;
String name;
if (parse_options & FunctionNodeParseOptions::CheckForFunctionAndName) {
consume(TokenType::Function);
if (!is_generator) {
is_generator = match(TokenType::Asterisk);
if (is_generator) {
consume(TokenType::Asterisk);
parse_options = parse_options | FunctionNodeParseOptions::IsGeneratorFunction;
}
}
if (FunctionNodeType::must_have_name() || match_identifier())
name = consume_identifier().value();
else if (is_function_expression && (match(TokenType::Yield) || match(TokenType::Await)))
name = consume().value();
check_identifier_name_for_assignment_validity(name);
}
TemporaryChange generator_change(m_state.in_generator_function_context, is_generator);
consume(TokenType::ParenOpen);
i32 function_length = -1;
auto parameters = parse_formal_parameters(function_length, parse_options);
consume(TokenType::ParenClose);
if (function_length == -1)
function_length = parameters.size();
TemporaryChange change(m_state.in_function_context, true);
auto old_labels_in_scope = move(m_state.labels_in_scope);
ScopeGuard guard([&]() {
m_state.labels_in_scope = move(old_labels_in_scope);
});
m_state.function_parameters.append(parameters);
bool is_strict = false;
auto body = parse_block_statement(is_strict, !is_simple_parameter_list(parameters));
// If the function contains 'use strict' we need to check the parameters (again).
if (is_strict || is_generator) {
Vector<StringView> parameter_names;
for (auto& parameter : parameters) {
parameter.binding.visit(
[&](FlyString const& parameter_name) {
check_identifier_name_for_assignment_validity(parameter_name, is_strict);
if (is_generator && parameter_name == "yield"sv)
syntax_error("Parameter name 'yield' not allowed in this context");
for (auto& previous_name : parameter_names) {
if (previous_name == parameter_name) {
syntax_error(String::formatted("Duplicate parameter '{}' not allowed in strict mode", parameter_name));
}
}
parameter_names.append(parameter_name);
},
[&](NonnullRefPtr<BindingPattern> const& binding) {
binding->for_each_bound_name([&](auto& bound_name) {
if (is_generator && bound_name == "yield"sv)
syntax_error("Parameter name 'yield' not allowed in this context");
for (auto& previous_name : parameter_names) {
if (previous_name == bound_name) {
syntax_error(String::formatted("Duplicate parameter '{}' not allowed in strict mode", bound_name));
break;
}
}
parameter_names.append(bound_name);
});
});
}
check_identifier_name_for_assignment_validity(name, is_strict);
}
m_state.function_parameters.take_last();
scope.add_to_scope_node(body);
return create_ast_node<FunctionNodeType>(
{ m_state.current_token.filename(), rule_start.position(), position() },
name, move(body), move(parameters), function_length,
is_generator ? FunctionKind::Generator : FunctionKind::Regular, is_strict);
}
Vector<FunctionNode::Parameter> Parser::parse_formal_parameters(int& function_length, u8 parse_options)
{
auto rule_start = push_start();
bool has_default_parameter = false;
bool has_rest_parameter = false;
TemporaryChange formal_parameter_context_change { m_state.in_formal_parameter_context, true };
Vector<FunctionNode::Parameter> parameters;
auto consume_identifier_or_binding_pattern = [&]() -> Variant<FlyString, NonnullRefPtr<BindingPattern>> {
if (auto pattern = parse_binding_pattern(true))
return pattern.release_nonnull();
auto token = consume_identifier();
auto parameter_name = token.value();
check_identifier_name_for_assignment_validity(parameter_name);
for (auto& parameter : parameters) {
bool has_same_name = parameter.binding.visit(
[&](FlyString const& name) {
return name == parameter_name;
},
[&](NonnullRefPtr<BindingPattern> const& bindings) {
bool found_duplicate = false;
bindings->for_each_bound_name([&](auto& bound_name) {
if (bound_name == parameter_name)
found_duplicate = true;
});
return found_duplicate;
});
if (!has_same_name)
continue;
String message;
if (parse_options & FunctionNodeParseOptions::IsArrowFunction)
message = String::formatted("Duplicate parameter '{}' not allowed in arrow function", parameter_name);
else if (m_state.strict_mode)
message = String::formatted("Duplicate parameter '{}' not allowed in strict mode", parameter_name);
else if (has_default_parameter || match(TokenType::Equals))
message = String::formatted("Duplicate parameter '{}' not allowed in function with default parameter", parameter_name);
else if (has_rest_parameter)
message = String::formatted("Duplicate parameter '{}' not allowed in function with rest parameter", parameter_name);
if (!message.is_empty())
syntax_error(message, Position { token.line_number(), token.line_column() });
break;
}
return FlyString { token.value() };
};
while (match(TokenType::CurlyOpen) || match(TokenType::BracketOpen) || match_identifier() || match(TokenType::TripleDot)) {
if (parse_options & FunctionNodeParseOptions::IsGetterFunction)
syntax_error("Getter function must have no arguments");
if (parse_options & FunctionNodeParseOptions::IsSetterFunction && (parameters.size() >= 1 || match(TokenType::TripleDot)))
syntax_error("Setter function must have one argument");
auto is_rest = false;
if (match(TokenType::TripleDot)) {
consume();
has_rest_parameter = true;
function_length = parameters.size();
is_rest = true;
}
auto parameter = consume_identifier_or_binding_pattern();
RefPtr<Expression> default_value;
if (match(TokenType::Equals)) {
consume();
if (is_rest)
syntax_error("Rest parameter may not have a default initializer");
TemporaryChange change(m_state.in_function_context, true);
has_default_parameter = true;
function_length = parameters.size();
default_value = parse_expression(2);
bool is_generator = parse_options & FunctionNodeParseOptions::IsGeneratorFunction;
if ((is_generator || m_state.strict_mode) && default_value && default_value->fast_is<Identifier>() && static_cast<Identifier&>(*default_value).string() == "yield"sv)
syntax_error("Generator function parameter initializer cannot contain a reference to an identifier named \"yield\"");
}
parameters.append({ move(parameter), default_value, is_rest });
if (match(TokenType::ParenClose))
break;
consume(TokenType::Comma);
if (is_rest)
break;
}
if (parse_options & FunctionNodeParseOptions::IsSetterFunction && parameters.is_empty())
syntax_error("Setter function must have one argument");
return parameters;
}
static constexpr AK::Array<StringView, 36> s_reserved_words = { "break", "case", "catch", "class", "const", "continue", "debugger", "default", "delete", "do", "else", "enum", "export", "extends", "false", "finally", "for", "function", "if", "import", "in", "instanceof", "new", "null", "return", "super", "switch", "this", "throw", "true", "try", "typeof", "var", "void", "while", "with" };
RefPtr<BindingPattern> Parser::parse_binding_pattern(bool strict_checks)
{
auto rule_start = push_start();
TokenType closing_token;
bool is_object = true;
if (match(TokenType::BracketOpen)) {
consume();
closing_token = TokenType::BracketClose;
is_object = false;
} else if (match(TokenType::CurlyOpen)) {
consume();
closing_token = TokenType::CurlyClose;
} else {
return {};
}
Vector<BindingPattern::BindingEntry> entries;
while (!match(closing_token)) {
if (!is_object && match(TokenType::Comma)) {
consume();
entries.append(BindingPattern::BindingEntry {});
continue;
}
auto is_rest = false;
if (match(TokenType::TripleDot)) {
consume();
is_rest = true;
}
decltype(BindingPattern::BindingEntry::name) name = Empty {};
decltype(BindingPattern::BindingEntry::alias) alias = Empty {};
RefPtr<Expression> initializer = {};
if (is_object) {
if (match_identifier_name()) {
name = create_ast_node<Identifier>(
{ m_state.current_token.filename(), rule_start.position(), position() },
consume().value());
} else if (match(TokenType::BracketOpen)) {
consume();
auto expression = parse_expression(0);
if (strict_checks && m_state.in_generator_function_context && is<YieldExpression>(*expression))
syntax_error("Yield expression not allowed in formal parameter within generator context");
name = move(expression);
consume(TokenType::BracketClose);
} else {
expected("identifier or computed property name");
return {};
}
if (!is_rest && match(TokenType::Colon)) {
consume();
if (match(TokenType::CurlyOpen) || match(TokenType::BracketOpen)) {
auto binding_pattern = parse_binding_pattern(strict_checks);
if (!binding_pattern)
return {};
alias = binding_pattern.release_nonnull();
} else if (match_identifier_name()) {
alias = create_ast_node<Identifier>(
{ m_state.current_token.filename(), rule_start.position(), position() },
consume_identifier().value());
if (strict_checks && match(TokenType::BracketOpen))
syntax_error("Illegal property in declaration context");
} else {
expected("identifier or binding pattern");
return {};
}
}
} else {
if (match_identifier_name()) {
// BindingElement must always have an Empty name field
auto identifier_name = consume_identifier().value();
alias = create_ast_node<Identifier>(
{ m_state.current_token.filename(), rule_start.position(), position() },
identifier_name);
if (strict_checks) {
for (auto& entry : entries) {
if (entry.alias.has<NonnullRefPtr<Identifier>>()) {
if (entry.alias.get<NonnullRefPtr<Identifier>>()->string() == identifier_name)
syntax_error("Duplicate parameter names in bindings");
}
}
}
} else if (match(TokenType::BracketOpen) || match(TokenType::CurlyOpen)) {
auto pattern = parse_binding_pattern(strict_checks);
if (!pattern) {
expected("binding pattern");
return {};
}
alias = pattern.release_nonnull();
} else {
expected("identifier or binding pattern");
return {};
}
}
if (match(TokenType::Equals)) {
if (is_rest) {
syntax_error("Unexpected initializer after rest element");
return {};
}
consume();
initializer = parse_expression(2);
if (!initializer) {
expected("initialization expression");
return {};
}
if (strict_checks && is<YieldExpression>(*initializer))
syntax_error("Yield expression is not allow in formal parameter");
}
entries.append(BindingPattern::BindingEntry { move(name), move(alias), move(initializer), is_rest });
if (match(TokenType::Comma)) {
if (is_rest) {
syntax_error("Rest element may not be followed by a comma");
return {};
}
consume();
}
}
while (!is_object && match(TokenType::Comma))
consume();
consume(closing_token);
auto kind = is_object ? BindingPattern::Kind::Object : BindingPattern::Kind::Array;
auto pattern = adopt_ref(*new BindingPattern);
pattern->entries = move(entries);
pattern->kind = kind;
Vector<StringView> bound_names;
pattern->for_each_bound_name([&](auto& name) {
if (strict_checks) {
if (bound_names.contains_slow(name))
syntax_error("Duplicate parameter names in bindings");
bound_names.append(name);
}
check_identifier_name_for_assignment_validity(name);
});
return pattern;
}
NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_loop_variable_declaration)
{
auto rule_start = push_start();
DeclarationKind declaration_kind;
switch (m_state.current_token.type()) {
case TokenType::Var:
declaration_kind = DeclarationKind::Var;
break;
case TokenType::Let:
declaration_kind = DeclarationKind::Let;
break;
case TokenType::Const:
declaration_kind = DeclarationKind::Const;
break;
default:
VERIFY_NOT_REACHED();
}
consume();
NonnullRefPtrVector<VariableDeclarator> declarations;
for (;;) {
Variant<NonnullRefPtr<Identifier>, NonnullRefPtr<BindingPattern>, Empty> target { Empty() };
if (match_identifier()) {
auto identifier_start = push_start();
auto name = consume_identifier().value();
target = create_ast_node<Identifier>(
{ m_state.current_token.filename(), rule_start.position(), position() },
name);
check_identifier_name_for_assignment_validity(name);
if ((declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const) && name == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
// Check we do not have duplicates
auto check_declarations = [&](VariableDeclarator const& declarator) {
declarator.target().visit([&](NonnullRefPtr<Identifier> const& identifier) {
if (identifier->string() == name)
syntax_error(String::formatted("Identifier '{}' has already been declared", name), identifier_start.position()); },
[&](auto const&) {});
};
// In any previous let scope
if (!m_state.let_scopes.is_empty()) {
for (auto& decls : m_state.let_scopes.last()) {
for (auto& decl : decls.declarations()) {
check_declarations(decl);
}
}
}
// or this declaration
if (declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const) {
// FIXME: We should check the var_scopes here as well however this has edges cases with for loops.
// See duplicated-variable-declarations.js.
if (!m_state.function_parameters.is_empty() && m_state.current_scope->parent->type == Scope::Function) {
for (auto& parameter : m_state.function_parameters.last()) {
parameter.binding.visit(
[&](FlyString const& parameter_name) {
if (parameter_name == name)
syntax_error(String::formatted("Identifier '{}' has already been declared", name), identifier_start.position());
},
[&](NonnullRefPtr<BindingPattern> const& binding) {
binding->for_each_bound_name([&](auto& bound_name) {
if (bound_name == name)
syntax_error(String::formatted("Identifier '{}' has already been declared", name), identifier_start.position());
});
});
}
}
for (auto& declaration : declarations) {
check_declarations(declaration);
}
}
} else if (auto pattern = parse_binding_pattern(declaration_kind != DeclarationKind::Var)) {
target = pattern.release_nonnull();
if ((declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const)) {
target.get<NonnullRefPtr<BindingPattern>>()->for_each_bound_name([this, &declarations](auto& name) {
if (name == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
// FIXME: Again we do not check everything here see for example the parameter check above.
// However a more sustainable solution should be used since these checks are now spread over multiple sites.
for (auto& declaration : declarations) {
declaration.target().visit(
[&](NonnullRefPtr<Identifier> const& identifier) {
if (identifier->string() == name)
syntax_error(String::formatted("Identifier '{}' has already been declared", name));
},
[&](auto const&) {});
}
});
}
} else if (!m_state.in_generator_function_context && match(TokenType::Yield)) {
if (m_state.strict_mode)
syntax_error("Identifier must not be a reserved word in strict mode ('yield')");
target = create_ast_node<Identifier>(
{ m_state.current_token.filename(), rule_start.position(), position() },
consume().value());
}
if (target.has<Empty>()) {
expected("identifier or a binding pattern");
if (match(TokenType::Comma)) {
consume();
continue;
}
break;
}
RefPtr<Expression> init;
if (match(TokenType::Equals)) {
consume();
init = parse_expression(2);
} else if (!for_loop_variable_declaration && declaration_kind == DeclarationKind::Const) {
syntax_error("Missing initializer in 'const' variable declaration");
} else if (!for_loop_variable_declaration && target.has<NonnullRefPtr<BindingPattern>>()) {
syntax_error("Missing initializer in destructuring assignment");
}
if (init && is<FunctionExpression>(*init) && target.has<NonnullRefPtr<Identifier>>()) {
static_cast<FunctionExpression&>(*init).set_name_if_possible(target.get<NonnullRefPtr<Identifier>>()->string());
}
declarations.append(create_ast_node<VariableDeclarator>(
{ m_state.current_token.filename(), rule_start.position(), position() },
move(target).downcast<NonnullRefPtr<Identifier>, NonnullRefPtr<BindingPattern>>(),
move(init)));
if (match(TokenType::Comma)) {
consume();
continue;
}
break;
}
if (!for_loop_variable_declaration)
consume_or_insert_semicolon();
auto declaration = create_ast_node<VariableDeclaration>({ m_state.current_token.filename(), rule_start.position(), position() }, declaration_kind, move(declarations));
if (declaration_kind == DeclarationKind::Var) {
m_state.var_scopes.last().append(declaration);
} else {
m_state.let_scopes.last().append(declaration);
for (auto& declarator : declaration->declarations()) {
declarator.target().visit(
[&](const NonnullRefPtr<Identifier>& id) {
m_state.current_scope->lexical_declarations.set(id->string());
},
[&](const NonnullRefPtr<BindingPattern>& binding) {
binding->for_each_bound_name([&](const auto& name) {
m_state.current_scope->lexical_declarations.set(name);
});
});
}
}
return declaration;
}
NonnullRefPtr<ThrowStatement> Parser::parse_throw_statement()
{
auto rule_start = push_start();
consume(TokenType::Throw);
// Automatic semicolon insertion: terminate statement when throw is followed by newline
if (m_state.current_token.trivia_contains_line_terminator()) {
syntax_error("No line break is allowed between 'throw' and its expression");
return create_ast_node<ThrowStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, create_ast_node<ErrorExpression>({ m_state.current_token.filename(), rule_start.position(), position() }));
}
auto expression = parse_expression(0);
consume_or_insert_semicolon();
return create_ast_node<ThrowStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression));
}
NonnullRefPtr<BreakStatement> Parser::parse_break_statement()
{
auto rule_start = push_start();
consume(TokenType::Break);
FlyString target_label;
if (match(TokenType::Semicolon)) {
consume();
} else {
if (match(TokenType::Identifier) && !m_state.current_token.trivia_contains_line_terminator()) {
target_label = consume().value();
auto label = m_state.labels_in_scope.find(target_label);
if (label == m_state.labels_in_scope.end())
syntax_error(String::formatted("Label '{}' not found", target_label));
}
consume_or_insert_semicolon();
}
if (target_label.is_null() && !m_state.in_break_context)
syntax_error("Unlabeled 'break' not allowed outside of a loop or switch statement");
return create_ast_node<BreakStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, target_label);
}
NonnullRefPtr<ContinueStatement> Parser::parse_continue_statement()
{
auto rule_start = push_start();
if (!m_state.in_continue_context)
syntax_error("'continue' not allow outside of a loop");
consume(TokenType::Continue);
FlyString target_label;
if (match(TokenType::Semicolon)) {
consume();
return create_ast_node<ContinueStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, target_label);
}
if (match(TokenType::Identifier) && !m_state.current_token.trivia_contains_line_terminator()) {
target_label = consume().value();
auto label = m_state.labels_in_scope.find(target_label);
if (label == m_state.labels_in_scope.end() || !label->value)
syntax_error(String::formatted("Label '{}' not found or invalid", target_label));
}
consume_or_insert_semicolon();
return create_ast_node<ContinueStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, target_label);
}
NonnullRefPtr<ConditionalExpression> Parser::parse_conditional_expression(NonnullRefPtr<Expression> test)
{
auto rule_start = push_start();
consume(TokenType::QuestionMark);
auto consequent = parse_expression(2);
consume(TokenType::Colon);
auto alternate = parse_expression(2);
return create_ast_node<ConditionalExpression>({ m_state.current_token.filename(), rule_start.position(), position() }, move(test), move(consequent), move(alternate));
}
NonnullRefPtr<TryStatement> Parser::parse_try_statement()
{
auto rule_start = push_start();
consume(TokenType::Try);
auto block = parse_block_statement();
RefPtr<CatchClause> handler;
if (match(TokenType::Catch))
handler = parse_catch_clause();
RefPtr<BlockStatement> finalizer;
if (match(TokenType::Finally)) {
consume();
finalizer = parse_block_statement();
}
if (!handler && !finalizer)
syntax_error("try statement must have a 'catch' or 'finally' clause");
return create_ast_node<TryStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(block), move(handler), move(finalizer));
}
NonnullRefPtr<DoWhileStatement> Parser::parse_do_while_statement()
{
auto rule_start = push_start();
consume(TokenType::Do);
auto body = [&]() -> NonnullRefPtr<Statement> {
TemporaryChange break_change(m_state.in_break_context, true);
TemporaryChange continue_change(m_state.in_continue_context, true);
return parse_statement();
}();
consume(TokenType::While);
consume(TokenType::ParenOpen);
auto test = parse_expression(0);
consume(TokenType::ParenClose);
// Since ES 2015 a missing semicolon is inserted here, despite the regular ASI rules not applying
if (match(TokenType::Semicolon))
consume();
return create_ast_node<DoWhileStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(test), move(body));
}
NonnullRefPtr<WhileStatement> Parser::parse_while_statement()
{
auto rule_start = push_start();
consume(TokenType::While);
consume(TokenType::ParenOpen);
auto test = parse_expression(0);
consume(TokenType::ParenClose);
TemporaryChange break_change(m_state.in_break_context, true);
TemporaryChange continue_change(m_state.in_continue_context, true);
auto body = parse_statement();
return create_ast_node<WhileStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(test), move(body));
}
NonnullRefPtr<SwitchStatement> Parser::parse_switch_statement()
{
auto rule_start = push_start();
consume(TokenType::Switch);
consume(TokenType::ParenOpen);
auto determinant = parse_expression(0);
consume(TokenType::ParenClose);
consume(TokenType::CurlyOpen);
NonnullRefPtrVector<SwitchCase> cases;
auto has_default = false;
while (match(TokenType::Case) || match(TokenType::Default)) {
if (match(TokenType::Default)) {
if (has_default)
syntax_error("Multiple 'default' clauses in switch statement");
has_default = true;
}
cases.append(parse_switch_case());
}
consume(TokenType::CurlyClose);
return create_ast_node<SwitchStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(determinant), move(cases));
}
NonnullRefPtr<WithStatement> Parser::parse_with_statement()
{
auto rule_start = push_start();
consume(TokenType::With);
consume(TokenType::ParenOpen);
auto object = parse_expression(0);
consume(TokenType::ParenClose);
auto body = parse_statement();
return create_ast_node<WithStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(object), move(body));
}
NonnullRefPtr<SwitchCase> Parser::parse_switch_case()
{
auto rule_start = push_start();
RefPtr<Expression> test;
if (consume().type() == TokenType::Case) {
test = parse_expression(0);
}
consume(TokenType::Colon);
NonnullRefPtrVector<Statement> consequent;
TemporaryChange break_change(m_state.in_break_context, true);
for (;;) {
if (match_declaration())
consequent.append(parse_declaration());
else if (match_statement())
consequent.append(parse_statement());
else
break;
}
return create_ast_node<SwitchCase>({ m_state.current_token.filename(), rule_start.position(), position() }, move(test), move(consequent));
}
NonnullRefPtr<CatchClause> Parser::parse_catch_clause()
{
auto rule_start = push_start();
consume(TokenType::Catch);
FlyString parameter;
RefPtr<BindingPattern> pattern_parameter;
auto should_expect_parameter = false;
if (match(TokenType::ParenOpen)) {
should_expect_parameter = true;
consume();
if (match_identifier_name() && (!match(TokenType::Yield) || !m_state.in_generator_function_context))
parameter = consume().value();
else
pattern_parameter = parse_binding_pattern(true);
consume(TokenType::ParenClose);
}
if (should_expect_parameter && parameter.is_empty() && !pattern_parameter)
expected("an identifier or a binding pattern");
if (pattern_parameter)
pattern_parameter->for_each_bound_name([this](auto& name) { check_identifier_name_for_assignment_validity(name); });
if (!parameter.is_empty())
check_identifier_name_for_assignment_validity(parameter);
auto body = parse_block_statement();
if (pattern_parameter) {
return create_ast_node<CatchClause>(
{ m_state.current_token.filename(), rule_start.position(), position() },
pattern_parameter.release_nonnull(),
move(body));
}
return create_ast_node<CatchClause>(
{ m_state.current_token.filename(), rule_start.position(), position() },
move(parameter),
move(body));
}
NonnullRefPtr<IfStatement> Parser::parse_if_statement()
{
auto rule_start = push_start();
auto parse_function_declaration_as_block_statement = [&] {
// https://tc39.es/ecma262/#sec-functiondeclarations-in-ifstatement-statement-clauses
// Code matching this production is processed as if each matching occurrence of
// FunctionDeclaration[?Yield, ?Await, ~Default] was the sole StatementListItem
// of a BlockStatement occupying that position in the source code.
VERIFY(match(TokenType::Function));
ScopePusher scope(*this, ScopePusher::Let, Parser::Scope::Block);
auto block = create_ast_node<BlockStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
auto declaration = parse_declaration();
VERIFY(is<FunctionDeclaration>(*declaration));
auto& function_declaration = static_cast<FunctionDeclaration const&>(*declaration);
if (function_declaration.kind() == FunctionKind::Generator)
syntax_error("Generator functions can only be declared in top-level or within a block");
block->append(move(declaration));
scope.add_to_scope_node(block);
return block;
};
consume(TokenType::If);
consume(TokenType::ParenOpen);
auto predicate = parse_expression(0);
consume(TokenType::ParenClose);
RefPtr<Statement> consequent;
if (!m_state.strict_mode && match(TokenType::Function))
consequent = parse_function_declaration_as_block_statement();
else
consequent = parse_statement();
RefPtr<Statement> alternate;
if (match(TokenType::Else)) {
consume();
if (!m_state.strict_mode && match(TokenType::Function))
alternate = parse_function_declaration_as_block_statement();
else
alternate = parse_statement();
}
return create_ast_node<IfStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(predicate), move(*consequent), move(alternate));
}
NonnullRefPtr<Statement> Parser::parse_for_statement()
{
auto rule_start = push_start();
auto match_for_in_of = [&]() {
return match(TokenType::In) || (match(TokenType::Identifier) && m_state.current_token.original_value() == "of");
};
consume(TokenType::For);
consume(TokenType::ParenOpen);
bool in_scope = false;
ScopeGuard guard([&]() {
if (in_scope)
m_state.let_scopes.take_last();
});
RefPtr<ASTNode> init;
if (!match(TokenType::Semicolon)) {
if (match_variable_declaration()) {
if (!match(TokenType::Var)) {
m_state.let_scopes.append(NonnullRefPtrVector<VariableDeclaration>());
in_scope = true;
}
init = parse_variable_declaration(true);
if (match_for_in_of())
return parse_for_in_of_statement(*init);
if (static_cast<VariableDeclaration&>(*init).declaration_kind() == DeclarationKind::Const) {
for (auto& declaration : static_cast<VariableDeclaration&>(*init).declarations()) {
if (!declaration.init())
syntax_error("Missing initializer in 'const' variable declaration");
}
}
} else if (match_expression()) {
init = parse_expression(0, Associativity::Right, { TokenType::In });
if (match_for_in_of())
return parse_for_in_of_statement(*init);
} else {
syntax_error("Unexpected token in for loop");
}
}
consume(TokenType::Semicolon);
RefPtr<Expression> test;
if (!match(TokenType::Semicolon))
test = parse_expression(0);
consume(TokenType::Semicolon);
RefPtr<Expression> update;
if (!match(TokenType::ParenClose))
update = parse_expression(0);
consume(TokenType::ParenClose);
TemporaryChange break_change(m_state.in_break_context, true);
TemporaryChange continue_change(m_state.in_continue_context, true);
auto body = parse_statement();
return create_ast_node<ForStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(init), move(test), move(update), move(body));
}
NonnullRefPtr<Statement> Parser::parse_for_in_of_statement(NonnullRefPtr<ASTNode> lhs)
{
auto rule_start = push_start();
if (is<VariableDeclaration>(*lhs)) {
auto declarations = static_cast<VariableDeclaration&>(*lhs).declarations();
if (declarations.size() > 1)
syntax_error("multiple declarations not allowed in for..in/of");
if (declarations.size() < 1)
syntax_error("need exactly one variable declaration in for..in/of");
else if (declarations.first().init() != nullptr)
syntax_error("variable initializer not allowed in for..in/of");
} else if (!lhs->is_identifier() && !is<ObjectExpression>(*lhs) && !is<MemberExpression>(*lhs) && !is<ArrayExpression>(*lhs)) {
syntax_error(String::formatted("Invalid left-hand side in for-loop ('{}')", lhs->class_name()));
}
auto in_or_of = consume();
if (in_or_of.type() != TokenType::In) {
if (is<MemberExpression>(*lhs)) {
auto& member = static_cast<MemberExpression const&>(*lhs);
if (member.object().is_identifier() && static_cast<Identifier const&>(member.object()).string() == "let"sv)
syntax_error("For of statement may not start with let.");
}
}
auto rhs = parse_expression(0);
consume(TokenType::ParenClose);
TemporaryChange break_change(m_state.in_break_context, true);
TemporaryChange continue_change(m_state.in_continue_context, true);
auto body = parse_statement();
if (in_or_of.type() == TokenType::In)
return create_ast_node<ForInStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(lhs), move(rhs), move(body));
return create_ast_node<ForOfStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(lhs), move(rhs), move(body));
}
NonnullRefPtr<DebuggerStatement> Parser::parse_debugger_statement()
{
auto rule_start = push_start();
consume(TokenType::Debugger);
consume_or_insert_semicolon();
return create_ast_node<DebuggerStatement>({ m_state.current_token.filename(), rule_start.position(), position() });
}
bool Parser::match(TokenType type) const
{
return m_state.current_token.type() == type;
}
bool Parser::match_expression() const
{
auto type = m_state.current_token.type();
return type == TokenType::BoolLiteral
|| type == TokenType::NumericLiteral
|| type == TokenType::BigIntLiteral
|| type == TokenType::StringLiteral
|| type == TokenType::TemplateLiteralStart
|| type == TokenType::NullLiteral
|| match_identifier()
|| type == TokenType::New
|| type == TokenType::Class
|| type == TokenType::CurlyOpen
|| type == TokenType::BracketOpen
|| type == TokenType::ParenOpen
|| type == TokenType::Function
|| type == TokenType::This
|| type == TokenType::Super
|| type == TokenType::RegexLiteral
|| type == TokenType::Slash // Wrongly recognized regex by lexer
|| type == TokenType::SlashEquals // Wrongly recognized regex by lexer (/=a/ is a valid regex)
|| type == TokenType::Yield
|| match_unary_prefixed_expression();
}
bool Parser::match_unary_prefixed_expression() const
{
auto type = m_state.current_token.type();
return type == TokenType::PlusPlus
|| type == TokenType::MinusMinus
|| type == TokenType::ExclamationMark
|| type == TokenType::Tilde
|| type == TokenType::Plus
|| type == TokenType::Minus
|| type == TokenType::Typeof
|| type == TokenType::Void
|| type == TokenType::Delete;
}
bool Parser::match_secondary_expression(const Vector<TokenType>& forbidden) const
{
auto type = m_state.current_token.type();
if (forbidden.contains_slow(type))
return false;
return type == TokenType::Plus
|| type == TokenType::PlusEquals
|| type == TokenType::Minus
|| type == TokenType::MinusEquals
|| type == TokenType::Asterisk
|| type == TokenType::AsteriskEquals
|| type == TokenType::Slash
|| type == TokenType::SlashEquals
|| type == TokenType::Percent
|| type == TokenType::PercentEquals
|| type == TokenType::DoubleAsterisk
|| type == TokenType::DoubleAsteriskEquals
|| type == TokenType::Equals
|| type == TokenType::EqualsEqualsEquals
|| type == TokenType::ExclamationMarkEqualsEquals
|| type == TokenType::EqualsEquals
|| type == TokenType::ExclamationMarkEquals
|| type == TokenType::GreaterThan
|| type == TokenType::GreaterThanEquals
|| type == TokenType::LessThan
|| type == TokenType::LessThanEquals
|| type == TokenType::ParenOpen
|| type == TokenType::Period
|| type == TokenType::BracketOpen
|| (type == TokenType::PlusPlus && !m_state.current_token.trivia_contains_line_terminator())
|| (type == TokenType::MinusMinus && !m_state.current_token.trivia_contains_line_terminator())
|| type == TokenType::In
|| type == TokenType::Instanceof
|| type == TokenType::QuestionMark
|| type == TokenType::Ampersand
|| type == TokenType::AmpersandEquals
|| type == TokenType::Pipe
|| type == TokenType::PipeEquals
|| type == TokenType::Caret
|| type == TokenType::CaretEquals
|| type == TokenType::ShiftLeft
|| type == TokenType::ShiftLeftEquals
|| type == TokenType::ShiftRight
|| type == TokenType::ShiftRightEquals
|| type == TokenType::UnsignedShiftRight
|| type == TokenType::UnsignedShiftRightEquals
|| type == TokenType::DoubleAmpersand
|| type == TokenType::DoubleAmpersandEquals
|| type == TokenType::DoublePipe
|| type == TokenType::DoublePipeEquals
|| type == TokenType::DoubleQuestionMark
|| type == TokenType::DoubleQuestionMarkEquals;
}
bool Parser::match_statement() const
{
auto type = m_state.current_token.type();
return match_expression()
|| type == TokenType::Return
|| type == TokenType::Yield
|| type == TokenType::Do
|| type == TokenType::If
|| type == TokenType::Throw
|| type == TokenType::Try
|| type == TokenType::While
|| type == TokenType::With
|| type == TokenType::For
|| type == TokenType::CurlyOpen
|| type == TokenType::Switch
|| type == TokenType::Break
|| type == TokenType::Continue
|| type == TokenType::Var
|| type == TokenType::Debugger
|| type == TokenType::Semicolon;
}
bool Parser::match_export_or_import() const
{
auto type = m_state.current_token.type();
return type == TokenType::Export
|| type == TokenType::Import;
}
bool Parser::match_declaration()
{
auto type = m_state.current_token.type();
if (type == TokenType::Let && !m_state.strict_mode) {
return try_match_let_declaration();
}
return type == TokenType::Function
|| type == TokenType::Class
|| type == TokenType::Const
|| type == TokenType::Let;
}
Token Parser::next_token()
{
save_state();
consume();
auto token_after = m_state.current_token;
load_state();
return token_after;
}
bool Parser::try_match_let_declaration()
{
VERIFY(m_state.current_token.type() == TokenType::Let);
auto token_after = next_token();
if (token_after.is_identifier_name() && token_after.value() != "in"sv)
return true;
if (token_after.type() == TokenType::CurlyOpen || token_after.type() == TokenType::BracketOpen)
return true;
return false;
}
bool Parser::match_variable_declaration()
{
auto type = m_state.current_token.type();
if (type == TokenType::Let && !m_state.strict_mode) {
return try_match_let_declaration();
}
return type == TokenType::Var
|| type == TokenType::Let
|| type == TokenType::Const;
}
bool Parser::match_identifier() const
{
if (m_state.current_token.type() == TokenType::EscapedKeyword) {
if (m_state.current_token.value() == "let"sv)
return !m_state.strict_mode;
if (m_state.current_token.value() == "yield"sv)
return !m_state.strict_mode && !m_state.in_generator_function_context;
return true;
}
return m_state.current_token.type() == TokenType::Identifier
|| (m_state.current_token.type() == TokenType::Let && !m_state.strict_mode)
|| (m_state.current_token.type() == TokenType::Await && !m_state.strict_mode)
|| (m_state.current_token.type() == TokenType::Yield && !m_state.in_generator_function_context && !m_state.strict_mode); // See note in Parser::parse_identifier().
}
bool Parser::match_identifier_name() const
{
return m_state.current_token.is_identifier_name();
}
bool Parser::match_property_key() const
{
auto type = m_state.current_token.type();
return match_identifier_name()
|| type == TokenType::BracketOpen
|| type == TokenType::StringLiteral
|| type == TokenType::NumericLiteral
|| type == TokenType::BigIntLiteral;
}
bool Parser::done() const
{
return match(TokenType::Eof);
}
Token Parser::consume()
{
auto old_token = m_state.current_token;
m_state.current_token = m_state.lexer.next();
return old_token;
}
void Parser::consume_or_insert_semicolon()
{
// Semicolon was found and will be consumed
if (match(TokenType::Semicolon)) {
consume();
return;
}
// Insert semicolon if...
// ...token is preceded by one or more newlines
if (m_state.current_token.trivia_contains_line_terminator())
return;
// ...token is a closing curly brace
if (match(TokenType::CurlyClose))
return;
// ...token is eof
if (match(TokenType::Eof))
return;
// No rule for semicolon insertion applies -> syntax error
expected("Semicolon");
}
Token Parser::consume_identifier()
{
if (match(TokenType::Identifier))
return consume(TokenType::Identifier);
if (match(TokenType::EscapedKeyword))
return consume(TokenType::EscapedKeyword);
// Note that 'let' is not a reserved keyword, but our lexer considers it such
// As it's pretty nice to have that (for syntax highlighting and such), we'll
// special-case it here instead.
if (match(TokenType::Let)) {
if (m_state.strict_mode)
syntax_error("'let' is not allowed as an identifier in strict mode");
return consume();
}
if (match(TokenType::Yield)) {
if (m_state.strict_mode || m_state.in_generator_function_context)
syntax_error("Identifier must not be a reserved word in strict mode ('yield')");
return consume();
}
expected("Identifier");
return consume();
}
// https://tc39.es/ecma262/#prod-IdentifierReference
Token Parser::consume_identifier_reference()
{
if (match(TokenType::Identifier))
return consume(TokenType::Identifier);
if (match(TokenType::EscapedKeyword)) {
auto name = m_state.current_token.value();
if (name == "await"sv)
syntax_error("Identifier reference may not be 'await'");
else if (m_state.strict_mode && (name == "let"sv || name == "yield"sv))
syntax_error(String::formatted("'{}' is not allowed as an identifier in strict mode", name));
return consume();
}
// See note in Parser::parse_identifier().
if (match(TokenType::Let)) {
if (m_state.strict_mode)
syntax_error("'let' is not allowed as an identifier in strict mode");
return consume();
}
if (match(TokenType::Yield)) {
if (m_state.strict_mode)
syntax_error("Identifier reference may not be 'yield' in strict mode");
return consume();
}
if (match(TokenType::Await)) {
syntax_error("Identifier reference may not be 'await'");
return consume();
}
expected(Token::name(TokenType::Identifier));
return consume();
}
Token Parser::consume(TokenType expected_type)
{
if (!match(expected_type)) {
expected(Token::name(expected_type));
}
auto token = consume();
if (expected_type == TokenType::Identifier) {
if (m_state.strict_mode && is_strict_reserved_word(token.value()))
syntax_error(String::formatted("Identifier must not be a reserved word in strict mode ('{}')", token.value()));
}
return token;
}
Token Parser::consume_and_validate_numeric_literal()
{
auto is_unprefixed_octal_number = [](const StringView& value) {
return value.length() > 1 && value[0] == '0' && is_ascii_digit(value[1]);
};
auto literal_start = position();
auto token = consume(TokenType::NumericLiteral);
if (m_state.strict_mode && is_unprefixed_octal_number(token.value()))
syntax_error("Unprefixed octal number not allowed in strict mode", literal_start);
if (match_identifier_name() && m_state.current_token.trivia().is_empty())
syntax_error("Numeric literal must not be immediately followed by identifier");
return token;
}
void Parser::expected(const char* what)
{
auto message = m_state.current_token.message();
if (message.is_empty())
message = String::formatted("Unexpected token {}. Expected {}", m_state.current_token.name(), what);
syntax_error(message);
}
Position Parser::position() const
{
return {
m_state.current_token.line_number(),
m_state.current_token.line_column(),
m_state.current_token.offset(),
};
}
bool Parser::try_parse_arrow_function_expression_failed_at_position(const Position& position) const
{
auto it = m_token_memoizations.find(position);
if (it == m_token_memoizations.end())
return false;
return (*it).value.try_parse_arrow_function_expression_failed;
}
void Parser::set_try_parse_arrow_function_expression_failed_at_position(const Position& position, bool failed)
{
m_token_memoizations.set(position, { failed });
}
void Parser::syntax_error(const String& message, Optional<Position> position)
{
if (!position.has_value())
position = this->position();
m_state.errors.append({ message, position });
}
void Parser::save_state()
{
m_saved_state.append(m_state);
}
void Parser::load_state()
{
VERIFY(!m_saved_state.is_empty());
m_state = m_saved_state.take_last();
}
void Parser::discard_saved_state()
{
m_saved_state.take_last();
}
void Parser::check_identifier_name_for_assignment_validity(StringView name, bool force_strict)
{
// FIXME: this is now called from multiple places maybe the error message should be dynamic?
if (any_of(s_reserved_words, [&](auto& value) { return name == value; })) {
syntax_error("Binding pattern target may not be a reserved word");
} else if (m_state.strict_mode || force_strict) {
if (name.is_one_of("arguments"sv, "eval"sv))
syntax_error("Binding pattern target may not be called 'arguments' or 'eval' in strict mode");
else if (is_strict_reserved_word(name))
syntax_error(String::formatted("Binding pattern target may not be called '{}' in strict mode", name));
}
}
NonnullRefPtr<ImportStatement> Parser::parse_import_statement(Program& program)
{
auto rule_start = push_start();
if (program.type() != Program::Type::Module)
syntax_error("Cannot use import statement outside a module");
consume(TokenType::Import);
if (match(TokenType::StringLiteral)) {
auto module_name = consume(TokenType::StringLiteral).value();
return create_ast_node<ImportStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, module_name);
}
auto match_imported_binding = [&] {
return match_identifier() || match(TokenType::Yield) || match(TokenType::Await);
};
auto match_as = [&] {
return match(TokenType::Identifier) && m_state.current_token.original_value() == "as"sv;
};
bool continue_parsing = true;
struct ImportWithLocation {
ImportStatement::ImportEntry entry;
Position position;
};
Vector<ImportWithLocation> entries_with_location;
if (match_imported_binding()) {
auto id_position = position();
auto bound_name = consume().value();
entries_with_location.append({ { "default", bound_name }, id_position });
if (match(TokenType::Comma)) {
consume(TokenType::Comma);
} else {
continue_parsing = false;
}
}
if (!continue_parsing) {
// skip the rest
} else if (match(TokenType::Asterisk)) {
consume(TokenType::Asterisk);
if (!match_as())
syntax_error(String::formatted("Unexpected token: {}", m_state.current_token.name()));
consume(TokenType::Identifier);
if (match_imported_binding()) {
auto namespace_position = position();
auto namespace_name = consume().value();
entries_with_location.append({ { "*", namespace_name }, namespace_position });
} else {
syntax_error(String::formatted("Unexpected token: {}", m_state.current_token.name()));
}
} else if (match(TokenType::CurlyOpen)) {
consume(TokenType::CurlyOpen);
while (!done() && !match(TokenType::CurlyClose)) {
if (match_identifier_name()) {
auto require_as = !match_imported_binding();
auto name_position = position();
auto name = consume().value();
if (match_as()) {
consume(TokenType::Identifier);
auto alias_position = position();
auto alias = consume_identifier().value();
check_identifier_name_for_assignment_validity(alias);
entries_with_location.append({ { name, alias }, alias_position });
} else if (require_as) {
syntax_error(String::formatted("Unexpected reserved word '{}'", name));
} else {
check_identifier_name_for_assignment_validity(name);
entries_with_location.append({ { name, name }, name_position });
}
} else {
expected("identifier");
break;
}
if (!match(TokenType::Comma))
break;
consume(TokenType::Comma);
}
consume(TokenType::CurlyClose);
} else {
expected("import clauses");
}
auto from_statement = consume(TokenType::Identifier).value();
if (from_statement != "from"sv)
syntax_error(String::formatted("Expected 'from' got {}", from_statement));
auto module_name = consume(TokenType::StringLiteral).value();
Vector<ImportStatement::ImportEntry> entries;
entries.ensure_capacity(entries_with_location.size());
for (auto& entry : entries_with_location) {
for (auto& import_statement : program.imports()) {
if (import_statement.has_bound_name(entry.entry.local_name))
syntax_error(String::formatted("Identifier '{}' already declared", entry.entry.local_name), entry.position);
}
for (auto& new_entry : entries) {
if (new_entry.local_name == entry.entry.local_name)
syntax_error(String::formatted("Identifier '{}' already declared", entry.entry.local_name), entry.position);
}
entries.append(move(entry.entry));
}
return create_ast_node<ImportStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, module_name, move(entries));
}
NonnullRefPtr<ExportStatement> Parser::parse_export_statement(Program& program)
{
auto rule_start = push_start();
if (program.type() != Program::Type::Module)
syntax_error("Cannot use export statement outside a module");
auto match_as = [&] {
return match(TokenType::Identifier) && m_state.current_token.original_value() == "as"sv;
};
auto match_from = [&] {
return match(TokenType::Identifier) && m_state.current_token.original_value() == "from"sv;
};
auto match_default = [&] {
return match(TokenType::Default) && m_state.current_token.original_value() == "default"sv;
};
consume(TokenType::Export);
struct EntryAndLocation {
ExportStatement::ExportEntry entry;
Position position;
void to_module_request(String from_module)
{
entry.kind = ExportStatement::ExportEntry::Kind::ModuleRequest;
entry.module_request = from_module;
}
};
Vector<EntryAndLocation> entries_with_location;
RefPtr<ASTNode> expression = {};
if (match_default()) {
auto default_position = position();
consume(TokenType::Default);
String local_name;
if (match(TokenType::Class)) {
auto class_expression = parse_class_expression(false);
local_name = class_expression->name();
expression = move(class_expression);
} else if (match(TokenType::Function)) {
auto func_expr = parse_function_node<FunctionExpression>();
local_name = func_expr->name();
expression = move(func_expr);
// TODO: Allow async function
} else if (match_expression()) {
expression = parse_expression(2);
consume_or_insert_semicolon();
local_name = "*default*";
} else {
expected("Declaration or assignment expression");
}
entries_with_location.append({ { "default", local_name }, default_position });
} else {
enum FromSpecifier {
NotAllowed,
Optional,
Required
} check_for_from { NotAllowed };
if (match(TokenType::Asterisk)) {
auto asterisk_position = position();
consume(TokenType::Asterisk);
if (match_as()) {
consume(TokenType::Identifier);
if (match_identifier_name()) {
auto namespace_position = position();
auto exported_name = consume().value();
entries_with_location.append({ { exported_name, "*" }, namespace_position });
} else {
expected("identifier");
}
} else {
entries_with_location.append({ { {}, "*" }, asterisk_position });
}
check_for_from = Required;
} else if (match_declaration()) {
auto decl_position = position();
auto declaration = parse_declaration();
if (is<FunctionDeclaration>(*declaration)) {
auto& func = static_cast<FunctionDeclaration&>(*declaration);
entries_with_location.append({ { func.name(), func.name() }, func.source_range().start });
} else if (is<ClassDeclaration>(*declaration)) {
auto& class_declaration = static_cast<ClassDeclaration&>(*declaration);
entries_with_location.append({ { class_declaration.class_name(), class_declaration.class_name() }, class_declaration.source_range().start });
} else {
VERIFY(is<VariableDeclaration>(*declaration));
auto& variables = static_cast<VariableDeclaration&>(*declaration);
for (auto& decl : variables.declarations()) {
decl.target().visit(
[&](NonnullRefPtr<Identifier> const& identifier) {
entries_with_location.append({ { identifier->string(), identifier->string() }, identifier->source_range().start });
},
[&](NonnullRefPtr<BindingPattern> const& binding) {
binding->for_each_bound_name([&](auto& name) {
entries_with_location.append({ { name, name }, decl_position });
});
});
}
}
expression = declaration;
} else if (match(TokenType::Var)) {
auto variable_position = position();
auto variable_declaration = parse_variable_declaration();
for (auto& decl : variable_declaration->declarations()) {
decl.target().visit(
[&](NonnullRefPtr<Identifier> const& identifier) {
entries_with_location.append({ { identifier->string(), identifier->string() }, identifier->source_range().start });
},
[&](NonnullRefPtr<BindingPattern> const& binding) {
binding->for_each_bound_name([&](auto& name) {
entries_with_location.append({ { name, name }, variable_position });
});
});
}
expression = variable_declaration;
} else if (match(TokenType::CurlyOpen)) {
consume(TokenType::CurlyOpen);
while (!done() && !match(TokenType::CurlyClose)) {
if (match_identifier_name()) {
auto identifier_position = position();
auto identifier = consume().value();
if (match_as()) {
consume(TokenType::Identifier);
if (match_identifier_name()) {
auto export_name = consume().value();
entries_with_location.append({ { export_name, identifier }, identifier_position });
} else {
expected("identifier name");
}
} else {
entries_with_location.append({ { identifier, identifier }, identifier_position });
}
} else {
expected("identifier");
break;
}
if (!match(TokenType::Comma))
break;
consume(TokenType::Comma);
}
consume(TokenType::CurlyClose);
check_for_from = Optional;
} else {
syntax_error("Unexpected token 'export'", rule_start.position());
}
if (check_for_from != NotAllowed && match_from()) {
consume(TokenType::Identifier);
if (match(TokenType::StringLiteral)) {
auto from_specifier = consume().value();
for (auto& entry : entries_with_location)
entry.to_module_request(from_specifier);
} else {
expected("ModuleSpecifier");
}
} else if (check_for_from == Required) {
expected("from");
}
if (check_for_from != NotAllowed)
consume_or_insert_semicolon();
}
Vector<ExportStatement::ExportEntry> entries;
entries.ensure_capacity(entries_with_location.size());
for (auto& entry : entries_with_location) {
for (auto& export_statement : program.exports()) {
if (export_statement.has_export(entry.entry.export_name))
syntax_error(String::formatted("Duplicate export with name: '{}'", entry.entry.export_name), entry.position);
}
for (auto& new_entry : entries) {
if (new_entry.export_name == entry.entry.export_name)
syntax_error(String::formatted("Duplicate export with name: '{}'", entry.entry.export_name), entry.position);
}
entries.append(move(entry.entry));
}
return create_ast_node<ExportStatement>({ m_state.current_token.filename(), rule_start.position(), position() }, move(expression), move(entries));
}
}