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ladybird/Libraries/LibJS/Parser.h

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LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
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/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@gmx.de>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
LibJS: break or continue with nonexistent label is a syntax error
2020-10-08 17:49:08 +00:00
#include <AK/HashTable.h>
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
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#include <AK/NonnullRefPtr.h>
LibJS: Add Error::source_location_hint() This util function on the Error struct will take the source and then returns a string like this based on line and column information it has: foo bar ^ Which can be shown in the repl for syntax errors :^)
2020-05-26 11:57:50 +00:00
#include <AK/StringBuilder.h>
LibJS: Add strict mode Adds the ability for a scope (either a function or the entire program) to be in strict mode. Scopes default to non-strict mode. There are two ways to determine the strict-ness of the JS engine: 1. In the parser, this can be accessed with the parser_state variable m_is_strict_mode boolean. If true, the Parser is currently parsing in strict mode. This is done so that the Parser can generate syntax errors at parse time, which is required in some cases. 2. With Interpreter.is_strict_mode(). This allows strict mode checking at runtime as opposed to compile time. Additionally, in order to test this, a global isStrictMode() function has been added to the JS ReplObject under the test-mode flag.
2020-05-28 05:22:08 +00:00
#include <LibJS/AST.h>
#include <LibJS/Lexer.h>
LibJS: Let parser keep track of errors Rather than printing them to stderr directly the parser now keeps a Vector<Error>, which allows the "owner" of the parser to consume them individually after parsing. The Error struct has a message, line number, column number and a to_string() helper function to format this information into a meaningful error message. The Function() constructor will now include an error message when throwing a SyntaxError.
2020-05-14 15:26:01 +00:00
#include <stdio.h>
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
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namespace JS {
LibJS: Add operator precedence parsing Obey precedence and associativity rules when parsing expressions with chained operators.
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enum class Associativity {
Left,
Right
};
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
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class Parser {
public:
explicit Parser(Lexer lexer);
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
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NonnullRefPtr<Program> parse_program();
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
LibJS: Parse FunctionExpressions FunctionExpression is mostly like FunctionDeclaration, except the name is optional. Share the parsing logic in parse_function_node<NodeType>. This allows us to do nice things like: document.addEventListener("DOMContentLoaded", function() { alert("Hello friends!"); });
2020-03-19 10:52:56 +00:00
template<typename FunctionNodeType>
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
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NonnullRefPtr<FunctionNodeType> parse_function_node(bool check_for_function_and_name = true, bool allow_super_property_lookup = false, bool allow_super_constructor_call = false);
LibJS: Share parameter parsing between regular and arrow functions This simplifies try_parse_arrow_function_expression() and fixes a few cases that should not produce an arrow function AST but did: (a,,) => {} (a b) => {} (a ...b) => {} (...b a) => {} The new parsing logic checks whether parens are expected and uses parse_function_parameters() if so, rolling back if a new syntax error occurs during that. Otherwise it's just an identifier in which case we parse the single parameter ourselves.
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Vector<FunctionNode::Parameter> parse_function_parameters(int& function_length);
LibJS: Parse FunctionExpressions FunctionExpression is mostly like FunctionDeclaration, except the name is optional. Share the parsing logic in parse_function_node<NodeType>. This allows us to do nice things like: document.addEventListener("DOMContentLoaded", function() { alert("Hello friends!"); });
2020-03-19 10:52:56 +00:00
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
2020-03-18 10:23:53 +00:00
NonnullRefPtr<Statement> parse_statement();
NonnullRefPtr<BlockStatement> parse_block_statement();
LibJS: Strict mode is now handled by Functions and Programs, not Blocks Since blocks can't be strict by themselves, it makes no sense for them to store whether or not they are strict. Strict-ness is now stored in the Program and FunctionNode ASTNodes. Fixes issue #3641
2020-10-04 00:02:43 +00:00
NonnullRefPtr<BlockStatement> parse_block_statement(bool& is_strict);
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
2020-03-18 10:23:53 +00:00
NonnullRefPtr<ReturnStatement> parse_return_statement();
LibJS: Implement basic for..in and for..of loops
2020-04-21 18:21:26 +00:00
NonnullRefPtr<VariableDeclaration> parse_variable_declaration(bool with_semicolon = true);
NonnullRefPtr<Statement> parse_for_statement();
NonnullRefPtr<Statement> parse_for_in_of_statement(NonnullRefPtr<ASTNode> lhs);
LibJS: Parse "if" statements This patch implements basic parsing of "if" statements. We don't yet support parsing "else", so I added a FIXME about that.
2020-03-21 17:40:17 +00:00
NonnullRefPtr<IfStatement> parse_if_statement();
LibJS: Implement "throw" You can now throw an expression to the nearest catcher! :^) To support throwing arbitrary values, I added an Exception class that sits as a wrapper around whatever is thrown. In the future it will be a logical place to store a call stack.
2020-03-24 21:03:50 +00:00
NonnullRefPtr<ThrowStatement> parse_throw_statement();
LibJS: Parse "try", "catch" and "finally" This is the first step towards support exceptions. :^)
2020-03-24 13:03:55 +00:00
NonnullRefPtr<TryStatement> parse_try_statement();
NonnullRefPtr<CatchClause> parse_catch_clause();
LibJS: Lexer and parser support for "switch" statements
2020-03-29 11:09:54 +00:00
NonnullRefPtr<SwitchStatement> parse_switch_statement();
NonnullRefPtr<SwitchCase> parse_switch_case();
NonnullRefPtr<BreakStatement> parse_break_statement();
LibJS: Add support for "continue" inside "for" statements :^)
2020-04-04 22:22:42 +00:00
NonnullRefPtr<ContinueStatement> parse_continue_statement();
LibJS: Add support for do..while statements
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NonnullRefPtr<DoWhileStatement> parse_do_while_statement();
LibJS: Parse while statements
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NonnullRefPtr<WhileStatement> parse_while_statement();
LibJS: Implement (no-op) debugger statement
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NonnullRefPtr<DebuggerStatement> parse_debugger_statement();
LibJS: Implement ConditionalExpression (ternary "?:" operator)
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NonnullRefPtr<ConditionalExpression> parse_conditional_expression(NonnullRefPtr<Expression> test);
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
LibJS: Implement basic for..in and for..of loops
2020-04-21 18:21:26 +00:00
NonnullRefPtr<Expression> parse_expression(int min_precedence, Associativity associate = Associativity::Right, Vector<TokenType> forbidden = {});
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
2020-03-18 10:23:53 +00:00
NonnullRefPtr<Expression> parse_primary_expression();
NonnullRefPtr<Expression> parse_unary_prefixed_expression();
LibJS: Lex and parse regex literals, add RegExp objects This adds regex parsing/lexing, as well as a relatively empty RegExpObject. The purpose of this patch is to allow the engine to not get hung up on parsing regexes. This will aid in finding new syntax errors (say, from google or twitter) without having to replace all of their regexes first!
2020-06-03 23:05:49 +00:00
NonnullRefPtr<RegExpLiteral> parse_regexp_literal();
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
2020-03-18 10:23:53 +00:00
NonnullRefPtr<ObjectExpression> parse_object_expression();
LibJS: Parse ArrayExpression and start implementing Array objects Note that property lookup is not functional yet.
2020-03-20 19:29:57 +00:00
NonnullRefPtr<ArrayExpression> parse_array_expression();
LibJS: Handle hex and unicode escape sequences in string literals Introduces the following syntax: '\x55' '\u26a0' '\u{1f41e}'
2020-05-17 06:27:25 +00:00
NonnullRefPtr<StringLiteral> parse_string_literal(Token token);
LibJS: Add raw strings to tagged template literals When calling a function with a tagged template, the first array that is passed in now contains a "raw" property with the raw, escaped strings.
2020-05-06 23:34:14 +00:00
NonnullRefPtr<TemplateLiteral> parse_template_literal(bool is_tagged);
LibJS: Make the AST reference-counted This allows function objects to outlive the original parsed program without their ScopeNode disappearing.
2020-03-18 10:23:53 +00:00
NonnullRefPtr<Expression> parse_secondary_expression(NonnullRefPtr<Expression>, int min_precedence, Associativity associate = Associativity::Right);
NonnullRefPtr<CallExpression> parse_call_expression(NonnullRefPtr<Expression>);
LibJS: Implement basic support for the "new" keyword NewExpression mostly piggybacks on the existing CallExpression. The big difference is that "new" creates a new Object and passes it as |this| to the callee.
2020-03-28 15:33:52 +00:00
NonnullRefPtr<NewExpression> parse_new_expression();
LibJS: Add support for arrow functions
2020-03-30 13:26:09 +00:00
RefPtr<FunctionExpression> try_parse_arrow_function_expression(bool expect_parens);
LibJS: Parse labelled statements All statements now have an optional label string that can be null.
2020-05-28 18:09:19 +00:00
RefPtr<Statement> try_parse_labelled_statement();
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 18:31:21 +00:00
NonnullRefPtr<ClassDeclaration> parse_class_declaration();
NonnullRefPtr<ClassExpression> parse_class_expression(bool expect_class_name);
NonnullRefPtr<Expression> parse_property_key();
LibJS: Validate all assignment expressions, not just "=" The check for invalid lhs and assignment to eval/arguments in strict mode should happen for all kinds of assignment expressions, not just AssignmentOp::Assignment.
2020-10-04 22:58:57 +00:00
NonnullRefPtr<AssignmentExpression> parse_assignment_expression(AssignmentOp, NonnullRefPtr<Expression> lhs, int min_precedence, Associativity);
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
LibJS: Let parser keep track of errors Rather than printing them to stderr directly the parser now keeps a Vector<Error>, which allows the "owner" of the parser to consume them individually after parsing. The Error struct has a message, line number, column number and a to_string() helper function to format this information into a meaningful error message. The Function() constructor will now include an error message when throwing a SyntaxError.
2020-05-14 15:26:01 +00:00
struct Error {
String message;
size_t line;
size_t column;
String to_string() const
{
if (line == 0 || column == 0)
return message;
LibJS: Use String::formatted() for parser error messages
2020-10-04 13:53:15 +00:00
return String::formatted("{} (line: {}, column: {})", message, line, column);
LibJS: Let parser keep track of errors Rather than printing them to stderr directly the parser now keeps a Vector<Error>, which allows the "owner" of the parser to consume them individually after parsing. The Error struct has a message, line number, column number and a to_string() helper function to format this information into a meaningful error message. The Function() constructor will now include an error message when throwing a SyntaxError.
2020-05-14 15:26:01 +00:00
}
LibJS: Add Error::source_location_hint() This util function on the Error struct will take the source and then returns a string like this based on line and column information it has: foo bar ^ Which can be shown in the repl for syntax errors :^)
2020-05-26 11:57:50 +00:00
String source_location_hint(const StringView& source, const char spacer = ' ', const char indicator = '^') const
{
if (line == 0 || column == 0)
return {};
StringBuilder builder;
LibJS: Fix out-of-range error in Parser::Error::source_location_hint
2020-05-28 14:37:00 +00:00
builder.append(source.split_view('\n', true)[line - 1]);
LibJS: Add Error::source_location_hint() This util function on the Error struct will take the source and then returns a string like this based on line and column information it has: foo bar ^ Which can be shown in the repl for syntax errors :^)
2020-05-26 11:57:50 +00:00
builder.append('\n');
for (size_t i = 0; i < column - 1; ++i)
builder.append(spacer);
builder.append(indicator);
return builder.build();
}
LibJS: Let parser keep track of errors Rather than printing them to stderr directly the parser now keeps a Vector<Error>, which allows the "owner" of the parser to consume them individually after parsing. The Error struct has a message, line number, column number and a to_string() helper function to format this information into a meaningful error message. The Function() constructor will now include an error message when throwing a SyntaxError.
2020-05-14 15:26:01 +00:00
};
bool has_errors() const { return m_parser_state.m_errors.size(); }
const Vector<Error>& errors() const { return m_parser_state.m_errors; }
void print_errors() const
{
for (auto& error : m_parser_state.m_errors)
fprintf(stderr, "SyntaxError: %s\n", error.to_string().characters());
}
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
private:
LibJS: Hoist variable declarations to the nearest relevant scope "var" declarations are hoisted to the nearest function scope, while "let" and "const" are hoisted to the nearest block scope. This is done by the parser, which keeps two scope stacks, one stack for the current var scope and one for the current let/const scope. When the interpreter enters a scope, we walk all of the declarations and insert them into the variable environment. We don't support the temporal dead zone for let/const yet.
2020-04-13 14:42:54 +00:00
friend class ScopePusher;
LibJS: Add operator precedence parsing Obey precedence and associativity rules when parsing expressions with chained operators.
2020-03-12 22:02:41 +00:00
Associativity operator_associativity(TokenType) const;
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
bool match_expression() const;
LibJS/Parser: Implement the parsing of unary/prefixed update expressions
2020-03-14 18:45:51 +00:00
bool match_unary_prefixed_expression() const;
LibJS: Implement basic for..in and for..of loops
2020-04-21 18:21:26 +00:00
bool match_secondary_expression(Vector<TokenType> forbidden = {}) const;
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
bool match_statement() const;
LibJS: Consume semicolon at the end of a statement A bunch of code was relying on this not happenind, in particular the parsing of "for" statements. Reorganized things so they work again.
2020-03-23 18:08:32 +00:00
bool match_variable_declaration() const;
LibJS: Allow reserved words as keys in object expressions.
2020-04-18 18:31:27 +00:00
bool match_identifier_name() const;
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 18:31:21 +00:00
bool match_property_key() const;
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
bool match(TokenType type) const;
bool done() const;
void expected(const char* what);
LibJS: Add Parser::syntax_error() helper Instead of having fprintf()s all over the place we can now use syntax_error("message") or syntax_error("message", line, column). This takes care of a consistent format, appending a newline and getting the line number and column of the current token if the last two params are omitted.
2020-04-29 20:37:51 +00:00
void syntax_error(const String& message, size_t line = 0, size_t column = 0);
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
Token consume();
Token consume(TokenType type);
LibJS: Implement automatic semicolon insertion
2020-04-17 13:05:58 +00:00
void consume_or_insert_semicolon();
LibJS: Add Parser save_state() and load_state() functions These functions allow us to try to parse ambiguous expressions (such as arrow function arguments in parentheses), and rewind the state of the Parser if an expression candidate failed to parse.
2020-03-30 13:24:43 +00:00
void save_state();
void load_state();
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
LibJS: Add strict mode Adds the ability for a scope (either a function or the entire program) to be in strict mode. Scopes default to non-strict mode. There are two ways to determine the strict-ness of the JS engine: 1. In the parser, this can be accessed with the parser_state variable m_is_strict_mode boolean. If true, the Parser is currently parsing in strict mode. This is done so that the Parser can generate syntax errors at parse time, which is required in some cases. 2. With Interpreter.is_strict_mode(). This allows strict mode checking at runtime as opposed to compile time. Additionally, in order to test this, a global isStrictMode() function has been added to the JS ReplObject under the test-mode flag.
2020-05-28 05:22:08 +00:00
enum class UseStrictDirectiveState {
None,
Looking,
Found,
};
LibJS: Add Parser save_state() and load_state() functions These functions allow us to try to parse ambiguous expressions (such as arrow function arguments in parentheses), and rewind the state of the Parser if an expression candidate failed to parse.
2020-03-30 13:24:43 +00:00
struct ParserState {
Lexer m_lexer;
Token m_current_token;
LibJS: Let parser keep track of errors Rather than printing them to stderr directly the parser now keeps a Vector<Error>, which allows the "owner" of the parser to consume them individually after parsing. The Error struct has a message, line number, column number and a to_string() helper function to format this information into a meaningful error message. The Function() constructor will now include an error message when throwing a SyntaxError.
2020-05-14 15:26:01 +00:00
Vector<Error> m_errors;
LibJS: Hoist variable declarations to the nearest relevant scope "var" declarations are hoisted to the nearest function scope, while "let" and "const" are hoisted to the nearest block scope. This is done by the parser, which keeps two scope stacks, one stack for the current var scope and one for the current let/const scope. When the interpreter enters a scope, we walk all of the declarations and insert them into the variable environment. We don't support the temporal dead zone for let/const yet.
2020-04-13 14:42:54 +00:00
Vector<NonnullRefPtrVector<VariableDeclaration>> m_var_scopes;
Vector<NonnullRefPtrVector<VariableDeclaration>> m_let_scopes;
LibJS: Hoist function declarations This patch adds function declaration hoisting. The mechanism is similar to var hoisting. Hoisted function declarations are to be put before the hoisted var declarations, hence they have to be treated separately.
2020-06-04 12:48:36 +00:00
Vector<NonnullRefPtrVector<FunctionDeclaration>> m_function_scopes;
LibJS: Add strict mode Adds the ability for a scope (either a function or the entire program) to be in strict mode. Scopes default to non-strict mode. There are two ways to determine the strict-ness of the JS engine: 1. In the parser, this can be accessed with the parser_state variable m_is_strict_mode boolean. If true, the Parser is currently parsing in strict mode. This is done so that the Parser can generate syntax errors at parse time, which is required in some cases. 2. With Interpreter.is_strict_mode(). This allows strict mode checking at runtime as opposed to compile time. Additionally, in order to test this, a global isStrictMode() function has been added to the JS ReplObject under the test-mode flag.
2020-05-28 05:22:08 +00:00
UseStrictDirectiveState m_use_strict_directive { UseStrictDirectiveState::None };
LibJS: break or continue with nonexistent label is a syntax error
2020-10-08 17:49:08 +00:00
HashTable<StringView> m_labels_in_scope;
LibJS: Add strict mode Adds the ability for a scope (either a function or the entire program) to be in strict mode. Scopes default to non-strict mode. There are two ways to determine the strict-ness of the JS engine: 1. In the parser, this can be accessed with the parser_state variable m_is_strict_mode boolean. If true, the Parser is currently parsing in strict mode. This is done so that the Parser can generate syntax errors at parse time, which is required in some cases. 2. With Interpreter.is_strict_mode(). This allows strict mode checking at runtime as opposed to compile time. Additionally, in order to test this, a global isStrictMode() function has been added to the JS ReplObject under the test-mode flag.
2020-05-28 05:22:08 +00:00
bool m_strict_mode { false };
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 18:31:21 +00:00
bool m_allow_super_property_lookup { false };
bool m_allow_super_constructor_call { false };
LibJS: Disallow 'return' outside of a function
2020-10-07 18:33:48 +00:00
bool m_in_function_context { false };
LibJS: Disallow 'continue' & 'break' outside of their respective scopes 'continue' is no longer allowed outside of a loop, and an unlabeled 'break' is not longer allowed outside of a loop or switch statement. Labeled 'break' statements are still allowed everywhere, even if the label does not exist.
2020-10-07 19:21:15 +00:00
bool m_in_break_context { false };
bool m_in_continue_context { false };
LibJS: Add Parser save_state() and load_state() functions These functions allow us to try to parse ambiguous expressions (such as arrow function arguments in parentheses), and rewind the state of the Parser if an expression candidate failed to parse.
2020-03-30 13:24:43 +00:00
explicit ParserState(Lexer);
};
ParserState m_parser_state;
LibJS: Add function default arguments Adds the ability for function arguments to have default values. This works for standard functions as well as arrow functions. Default values are not printed in a <function>.toString() call, as nodes cannot print their source string representation.
2020-05-02 18:46:39 +00:00
Vector<ParserState> m_saved_state;
LibJS: Add Javascript lexer and parser This adds a basic Javascript lexer and parser. It can parse the currently existing demo programs. More work needs to be done to turn it into a complete parser than can parse arbitrary JS Code. The lexer outputs tokens with preceeding whitespace and comments in the trivia member. This should allow us to generate the exact source code by concatenating the generated tokens. The parser is written in a way that it always returns a complete syntax tree. Error conditions are represented as nodes in the tree. This simplifies the code and allows it to be used as an early stage parser, e.g for parsing JS documents in an IDE while editing the source code.:
2020-03-11 18:27:43 +00:00
};
}
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