ladybird/Userland/Libraries/LibJS/Parser.h

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/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
* Copyright (c) 2021, David Tuin <davidot@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashTable.h>
#include <AK/NonnullRefPtr.h>
#include <AK/StringBuilder.h>
#include <LibJS/AST.h>
#include <LibJS/Lexer.h>
#include <LibJS/SourceRange.h>
#include <stdio.h>
namespace JS {
enum class Associativity {
Left,
Right
};
struct FunctionNodeParseOptions {
enum {
CheckForFunctionAndName = 1 << 0,
AllowSuperPropertyLookup = 1 << 1,
AllowSuperConstructorCall = 1 << 2,
IsGetterFunction = 1 << 3,
IsSetterFunction = 1 << 4,
IsArrowFunction = 1 << 5,
IsGeneratorFunction = 1 << 6,
IsAsyncFunction = 1 << 7,
};
};
LibJS: Make scoping follow the spec Before this we used an ad-hoc combination of references and 'variables' stored in a hashmap. This worked in most cases but is not spec like. Additionally hoisting, dynamically naming functions and scope analysis was not done properly. This patch fixes all of that by: - Implement BindingInitialization for destructuring assignment. - Implementing a new ScopePusher which tracks the lexical and var scoped declarations. This hoists functions to the top level if no lexical declaration name overlaps. Furthermore we do checking of redeclarations in the ScopePusher now requiring less checks all over the place. - Add methods for parsing the directives and statement lists instead of having that code duplicated in multiple places. This allows declarations to pushed to the appropriate scope more easily. - Remove the non spec way of storing 'variables' in DeclarativeEnvironment and make Reference follow the spec instead of checking both the bindings and 'variables'. - Remove all scoping related things from the Interpreter. And instead use environments as specified by the spec. This also includes fixing that NativeFunctions did not produce a valid FunctionEnvironment which could cause issues with callbacks and eval. All FunctionObjects now have a valid NewFunctionEnvironment implementation. - Remove execute_statements from Interpreter and instead use ASTNode::execute everywhere this simplifies AST.cpp as you no longer need to worry about which method to call. - Make ScopeNodes setup their own environment. This uses four different methods specified by the spec {Block, Function, Eval, Global}DeclarationInstantiation with the annexB extensions. - Implement and use NamedEvaluation where specified. Additionally there are fixes to things exposed by these changes to eval, {for, for-in, for-of} loops and assignment. Finally it also fixes some tests in test-js which where passing before but not now that we have correct behavior :^).
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class ScopePusher;
class Parser {
public:
explicit Parser(Lexer lexer, Program::Type program_type = Program::Type::Script);
NonnullRefPtr<Program> parse_program(bool starts_in_strict_mode = false);
template<typename FunctionNodeType>
NonnullRefPtr<FunctionNodeType> parse_function_node(u8 parse_options = FunctionNodeParseOptions::CheckForFunctionAndName);
Vector<FunctionNode::Parameter> parse_formal_parameters(int& function_length, u8 parse_options = 0);
enum class AllowDuplicates {
Yes,
No
};
enum class AllowMemberExpressions {
Yes,
No
};
RefPtr<BindingPattern> parse_binding_pattern(AllowDuplicates is_var_declaration = AllowDuplicates::No, AllowMemberExpressions allow_member_expressions = AllowMemberExpressions::No);
struct PrimaryExpressionParseResult {
NonnullRefPtr<Expression> result;
bool should_continue_parsing_as_expression { true };
};
NonnullRefPtr<Declaration> parse_declaration();
enum class AllowLabelledFunction {
No,
Yes
};
NonnullRefPtr<Statement> parse_statement(AllowLabelledFunction allow_labelled_function = AllowLabelledFunction::No);
NonnullRefPtr<BlockStatement> parse_block_statement();
NonnullRefPtr<FunctionBody> parse_function_body(Vector<FunctionDeclaration::Parameter> const& parameters, FunctionKind function_kind, bool& contains_direct_call_to_eval);
NonnullRefPtr<ReturnStatement> parse_return_statement();
NonnullRefPtr<VariableDeclaration> parse_variable_declaration(bool for_loop_variable_declaration = false);
NonnullRefPtr<Statement> parse_for_statement();
enum class IsForAwaitLoop {
No,
Yes
};
NonnullRefPtr<Statement> parse_for_in_of_statement(NonnullRefPtr<ASTNode> lhs, IsForAwaitLoop is_await);
NonnullRefPtr<IfStatement> parse_if_statement();
NonnullRefPtr<ThrowStatement> parse_throw_statement();
NonnullRefPtr<TryStatement> parse_try_statement();
NonnullRefPtr<CatchClause> parse_catch_clause();
NonnullRefPtr<SwitchStatement> parse_switch_statement();
NonnullRefPtr<SwitchCase> parse_switch_case();
NonnullRefPtr<BreakStatement> parse_break_statement();
NonnullRefPtr<ContinueStatement> parse_continue_statement();
NonnullRefPtr<DoWhileStatement> parse_do_while_statement();
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NonnullRefPtr<WhileStatement> parse_while_statement();
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NonnullRefPtr<WithStatement> parse_with_statement();
NonnullRefPtr<DebuggerStatement> parse_debugger_statement();
NonnullRefPtr<ConditionalExpression> parse_conditional_expression(NonnullRefPtr<Expression> test);
NonnullRefPtr<OptionalChain> parse_optional_chain(NonnullRefPtr<Expression> base);
NonnullRefPtr<Expression> parse_expression(int min_precedence, Associativity associate = Associativity::Right, const Vector<TokenType>& forbidden = {});
PrimaryExpressionParseResult parse_primary_expression();
NonnullRefPtr<Expression> parse_unary_prefixed_expression();
NonnullRefPtr<RegExpLiteral> parse_regexp_literal();
NonnullRefPtr<ObjectExpression> parse_object_expression();
NonnullRefPtr<ArrayExpression> parse_array_expression();
NonnullRefPtr<StringLiteral> parse_string_literal(const Token& token, bool in_template_literal = false);
NonnullRefPtr<TemplateLiteral> parse_template_literal(bool is_tagged);
NonnullRefPtr<Expression> parse_secondary_expression(NonnullRefPtr<Expression>, int min_precedence, Associativity associate = Associativity::Right);
NonnullRefPtr<Expression> parse_call_expression(NonnullRefPtr<Expression>);
NonnullRefPtr<NewExpression> parse_new_expression();
NonnullRefPtr<ClassDeclaration> parse_class_declaration();
NonnullRefPtr<ClassExpression> parse_class_expression(bool expect_class_name);
NonnullRefPtr<YieldExpression> parse_yield_expression();
NonnullRefPtr<AwaitExpression> parse_await_expression();
NonnullRefPtr<Expression> parse_property_key();
NonnullRefPtr<AssignmentExpression> parse_assignment_expression(AssignmentOp, NonnullRefPtr<Expression> lhs, int min_precedence, Associativity);
NonnullRefPtr<Identifier> parse_identifier();
NonnullRefPtr<ImportStatement> parse_import_statement(Program& program);
NonnullRefPtr<ExportStatement> parse_export_statement(Program& program);
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RefPtr<FunctionExpression> try_parse_arrow_function_expression(bool expect_parens, bool is_async = false);
RefPtr<Statement> try_parse_labelled_statement(AllowLabelledFunction allow_function);
RefPtr<MetaProperty> try_parse_new_target_expression();
RefPtr<MetaProperty> try_parse_import_meta_expression();
NonnullRefPtr<ImportCall> parse_import_call();
Vector<CallExpression::Argument> parse_arguments();
struct Error {
String message;
Optional<Position> position;
String to_string() const
{
if (!position.has_value())
return message;
return String::formatted("{} (line: {}, column: {})", message, position.value().line, position.value().column);
}
String source_location_hint(StringView source, const char spacer = ' ', const char indicator = '^') const
{
if (!position.has_value())
return {};
// We need to modify the source to match what the lexer considers one line - normalizing
// line terminators to \n is easier than splitting using all different LT characters.
String source_string = source.replace("\r\n", "\n").replace("\r", "\n").replace(LINE_SEPARATOR_STRING, "\n").replace(PARAGRAPH_SEPARATOR_STRING, "\n");
StringBuilder builder;
builder.append(source_string.split_view('\n', true)[position.value().line - 1]);
builder.append('\n');
for (size_t i = 0; i < position.value().column - 1; ++i)
builder.append(spacer);
builder.append(indicator);
return builder.build();
}
};
bool has_errors() const { return m_state.errors.size(); }
const Vector<Error>& errors() const { return m_state.errors; }
void print_errors(bool print_hint = true) const
{
for (auto& error : m_state.errors) {
if (print_hint) {
auto hint = error.source_location_hint(m_state.lexer.source());
if (!hint.is_empty())
warnln("{}", hint);
}
warnln("SyntaxError: {}", error.to_string());
}
}
struct TokenMemoization {
bool try_parse_arrow_function_expression_failed;
};
private:
friend class ScopePusher;
Associativity operator_associativity(TokenType) const;
bool match_expression() const;
bool match_unary_prefixed_expression() const;
bool match_secondary_expression(const Vector<TokenType>& forbidden = {}) const;
bool match_statement() const;
bool match_export_or_import() const;
bool match_declaration() const;
bool try_match_let_declaration() const;
bool match_variable_declaration() const;
bool match_identifier() const;
bool match_identifier_name() const;
bool match_property_key() const;
bool is_private_identifier_valid() const;
bool match(TokenType type) const;
bool done() const;
void expected(const char* what);
void syntax_error(const String& message, Optional<Position> = {});
Token consume();
Token consume_identifier();
Token consume_identifier_reference();
Token consume(TokenType type);
Token consume_and_validate_numeric_literal();
void consume_or_insert_semicolon();
void save_state();
void load_state();
void discard_saved_state();
Position position() const;
RefPtr<BindingPattern> synthesize_binding_pattern(Expression const& expression);
Token next_token() const;
void check_identifier_name_for_assignment_validity(StringView, bool force_strict = false);
bool try_parse_arrow_function_expression_failed_at_position(const Position&) const;
void set_try_parse_arrow_function_expression_failed_at_position(const Position&, bool);
bool match_invalid_escaped_keyword() const;
LibJS: Make scoping follow the spec Before this we used an ad-hoc combination of references and 'variables' stored in a hashmap. This worked in most cases but is not spec like. Additionally hoisting, dynamically naming functions and scope analysis was not done properly. This patch fixes all of that by: - Implement BindingInitialization for destructuring assignment. - Implementing a new ScopePusher which tracks the lexical and var scoped declarations. This hoists functions to the top level if no lexical declaration name overlaps. Furthermore we do checking of redeclarations in the ScopePusher now requiring less checks all over the place. - Add methods for parsing the directives and statement lists instead of having that code duplicated in multiple places. This allows declarations to pushed to the appropriate scope more easily. - Remove the non spec way of storing 'variables' in DeclarativeEnvironment and make Reference follow the spec instead of checking both the bindings and 'variables'. - Remove all scoping related things from the Interpreter. And instead use environments as specified by the spec. This also includes fixing that NativeFunctions did not produce a valid FunctionEnvironment which could cause issues with callbacks and eval. All FunctionObjects now have a valid NewFunctionEnvironment implementation. - Remove execute_statements from Interpreter and instead use ASTNode::execute everywhere this simplifies AST.cpp as you no longer need to worry about which method to call. - Make ScopeNodes setup their own environment. This uses four different methods specified by the spec {Block, Function, Eval, Global}DeclarationInstantiation with the annexB extensions. - Implement and use NamedEvaluation where specified. Additionally there are fixes to things exposed by these changes to eval, {for, for-in, for-of} loops and assignment. Finally it also fixes some tests in test-js which where passing before but not now that we have correct behavior :^).
2021-09-22 10:44:56 +00:00
bool parse_directive(ScopeNode& body);
void parse_statement_list(ScopeNode& output_node, AllowLabelledFunction allow_labelled_functions = AllowLabelledFunction::No);
struct RulePosition {
AK_MAKE_NONCOPYABLE(RulePosition);
AK_MAKE_NONMOVABLE(RulePosition);
public:
RulePosition(Parser& parser, Position position)
: m_parser(parser)
, m_position(position)
{
m_parser.m_rule_starts.append(position);
}
~RulePosition()
{
auto last = m_parser.m_rule_starts.take_last();
VERIFY(last.line == m_position.line);
VERIFY(last.column == m_position.column);
}
const Position& position() const { return m_position; }
private:
Parser& m_parser;
Position m_position;
};
[[nodiscard]] RulePosition push_start() { return { *this, position() }; }
struct ParserState {
Lexer lexer;
Token current_token;
Vector<Error> errors;
ScopePusher* current_scope_pusher { nullptr };
HashMap<StringView, Optional<Position>> labels_in_scope;
HashTable<StringView>* referenced_private_names { nullptr };
bool strict_mode { false };
bool allow_super_property_lookup { false };
bool allow_super_constructor_call { false };
bool in_function_context { false };
bool in_formal_parameter_context { false };
bool in_generator_function_context { false };
bool await_expression_is_valid { false };
bool in_arrow_function_context { false };
bool in_break_context { false };
bool in_continue_context { false };
bool string_legacy_octal_escape_sequence_in_scope { false };
bool in_class_field_initializer { false };
bool in_class_static_init_block { false };
bool function_might_need_arguments_object { false };
ParserState(Lexer, Program::Type);
};
class PositionKeyTraits {
public:
static int hash(const Position& position)
{
return int_hash(position.line) ^ int_hash(position.column);
}
static bool equals(const Position& a, const Position& b)
{
return a.column == b.column && a.line == b.line;
}
};
Vector<Position> m_rule_starts;
ParserState m_state;
FlyString m_filename;
Vector<ParserState> m_saved_state;
HashMap<Position, TokenMemoization, PositionKeyTraits> m_token_memoizations;
Program::Type m_program_type;
};
}