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ladybird/Userland/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.:
2020-03-11 18:27:43 +00:00
/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@gmx.de>
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
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* SPDX-License-Identifier: BSD-2-Clause
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
*/
#pragma once
LibJS: break or continue with nonexistent label is a syntax error
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#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: Track source positions all the way down to exceptions This makes exceptions have a trace of source positions too, which could probably be helpful in making fancier error tracebacks.
2020-12-28 17:15:22 +00:00
#include <LibJS/SourceRange.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: Refactor parse_function_node() bool parameters into bit flags I'm about to add even more options and a bunch of unnamed true/false arguments is really not helpful. Let's make this a single parse options parameter using bit flags.
2020-10-20 16:56:49 +00:00
struct FunctionNodeParseOptions {
enum {
CheckForFunctionAndName = 1 << 0,
AllowSuperPropertyLookup = 1 << 1,
AllowSuperConstructorCall = 1 << 2,
LibJS: Move checks for invalid getter/setter params to parse_function_node This allows us to provide better error messages as we can point the syntax error location to the exact first invalid parameter instead of always the end of the function within a object literal or class definition. Before this change: const Foo = { set bar() {} } ^ Uncaught exception: [SyntaxError]: Object setter property must have one argument (line: 1, column: 28) class Foo { set bar() {} } ^ Uncaught exception: [SyntaxError]: Class setter method must have one argument (line: 1, column: 26) After this change: const Foo = { set bar() {} } ^ Uncaught exception: [SyntaxError]: Setter function must have one argument (line: 1, column: 23) class Foo { set bar() {} } ^ Uncaught exception: [SyntaxError]: Setter function must have one argument (line: 1, column: 21) The only possible downside of this change is that class getters/setters and functions in objects are not distinguished in the message anymore - I don't think that's important though, and classes are (mostly) just syntactic sugar anyway.
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IsGetterFunction = 1 << 3,
IsSetterFunction = 1 << 4,
LibJS: Implement rules for duplicate function parameters - A regular function can have duplicate parameters except in strict mode or if its parameter list is not "simple" (has a default or rest parameter) - An arrow function can never have duplicate parameters Compared to other engines I opted for more useful syntax error messages than a generic "duplicate parameter name not allowed in this context": "use strict"; function test(foo, foo) {} ^ Uncaught exception: [SyntaxError]: Duplicate parameter 'foo' not allowed in strict mode (line: 1, column: 34) function test(foo, foo = 1) {} ^ Uncaught exception: [SyntaxError]: Duplicate parameter 'foo' not allowed in function with default parameter (line: 1, column: 20) function test(foo, ...foo) {} ^ Uncaught exception: [SyntaxError]: Duplicate parameter 'foo' not allowed in function with rest parameter (line: 1, column: 23) (foo, foo) => {} ^ Uncaught exception: [SyntaxError]: Duplicate parameter 'foo' not allowed in arrow function (line: 1, column: 7)
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IsArrowFunction = 1 << 5,
LibJS: Refactor parse_function_node() bool parameters into bit flags I'm about to add even more options and a bunch of unnamed true/false arguments is really not helpful. Let's make this a single parse options parameter using bit flags.
2020-10-20 16:56:49 +00:00
};
};
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!"); });
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template<typename FunctionNodeType>
LibJS: Refactor parse_function_node() bool parameters into bit flags I'm about to add even more options and a bunch of unnamed true/false arguments is really not helpful. Let's make this a single parse options parameter using bit flags.
2020-10-20 16:56:49 +00:00
NonnullRefPtr<FunctionNodeType> parse_function_node(u8 parse_options = FunctionNodeParseOptions::CheckForFunctionAndName);
LibJS: Move checks for invalid getter/setter params to parse_function_node This allows us to provide better error messages as we can point the syntax error location to the exact first invalid parameter instead of always the end of the function within a object literal or class definition. Before this change: const Foo = { set bar() {} } ^ Uncaught exception: [SyntaxError]: Object setter property must have one argument (line: 1, column: 28) class Foo { set bar() {} } ^ Uncaught exception: [SyntaxError]: Class setter method must have one argument (line: 1, column: 26) After this change: const Foo = { set bar() {} } ^ Uncaught exception: [SyntaxError]: Setter function must have one argument (line: 1, column: 23) class Foo { set bar() {} } ^ Uncaught exception: [SyntaxError]: Setter function must have one argument (line: 1, column: 21) The only possible downside of this change is that class getters/setters and functions in objects are not distinguished in the message anymore - I don't think that's important though, and classes are (mostly) just syntactic sugar anyway.
2020-10-20 17:32:51 +00:00
Vector<FunctionNode::Parameter> parse_function_parameters(int& function_length, u8 parse_options = 0);
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: Distinguish between statement and declaration This separates matching/parsing of statements and declarations and fixes a few edge cases where the parser would incorrectly accept a declaration where only a statement is allowed - for example: if (foo) const a = 1; for (var bar;;) function b() {} while (baz) class c {}
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NonnullRefPtr<Declaration> parse_declaration();
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: Require initializer for 'const' variable declaration
2020-10-30 19:08:45 +00:00
NonnullRefPtr<VariableDeclaration> parse_variable_declaration(bool for_loop_variable_declaration = false);
LibJS: Implement basic for..in and for..of loops
2020-04-21 18:21:26 +00:00
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
2020-04-04 19:29:23 +00:00
NonnullRefPtr<DoWhileStatement> parse_do_while_statement();
LibJS: Parse while statements
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NonnullRefPtr<WhileStatement> parse_while_statement();
LibJS: Parse "with" statements :^)
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NonnullRefPtr<WithStatement> parse_with_statement();
LibJS: Implement (no-op) debugger statement
2020-04-30 16:26:27 +00:00
NonnullRefPtr<DebuggerStatement> parse_debugger_statement();
LibJS: Implement ConditionalExpression (ternary "?:" operator)
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NonnullRefPtr<ConditionalExpression> parse_conditional_expression(NonnullRefPtr<Expression> test);
LibJS: Use const references to avoid some copies in the parser
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NonnullRefPtr<Expression> parse_expression(int min_precedence, Associativity associate = Associativity::Right, const 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: Use const references to avoid some copies in the parser
2021-02-24 08:58:24 +00:00
NonnullRefPtr<StringLiteral> parse_string_literal(const Token& token, bool in_template_literal = false);
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: 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: Implement 'new.target' This adds a new MetaProperty AST node which will be used for 'new.target' and 'import.meta' meta properties. The parser now distinguishes between "in function context" and "in arrow function context" (which is required for this). When encountering TokenType::New we will attempt to parse it as meta property and resort to regular new expression parsing if that fails, much like the parsing of labelled statements.
2020-11-02 21:27:42 +00:00
RefPtr<FunctionExpression> try_parse_arrow_function_expression(bool expect_parens);
RefPtr<Statement> try_parse_labelled_statement();
RefPtr<MetaProperty> try_parse_new_target_expression();
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
struct Error {
String message;
Optional<Position> position;
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
String to_string() const
{
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
if (!position.has_value())
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
return message;
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
return String::formatted("{} (line: {}, column: {})", message, position.value().line, position.value().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
{
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
if (!position.has_value())
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
return {};
LibJS: Support all line terminators (LF, CR, LS, PS) https://tc39.es/ecma262/#sec-line-terminators
2020-10-21 21:16:45 +00:00
// 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 };
source_string.replace("\r\n", "\n");
source_string.replace("\r", "\n");
source_string.replace(LINE_SEPARATOR, "\n");
source_string.replace(PARAGRAPH_SEPARATOR, "\n");
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
StringBuilder builder;
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
builder.append(source_string.split_view('\n', true)[position.value().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');
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
for (size_t i = 0; i < position.value().column - 1; ++i)
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(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
{
LibJS: Include source location hint in Parser::print_errors()
2020-12-06 14:50:39 +00:00
for (auto& error : m_parser_state.m_errors) {
auto hint = error.source_location_hint(m_parser_state.m_lexer.source());
if (!hint.is_empty())
warnln("{}", hint);
warnln("SyntaxError: {}", error.to_string());
}
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 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: Memoize failed calls of try_parse_arrow_function_expression()
2021-04-11 20:41:51 +00:00
struct TokenMemoization {
bool try_parse_arrow_function_expression_failed;
};
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: Use const references to avoid some copies in the parser
2021-02-24 08:58:24 +00:00
bool match_secondary_expression(const 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: Distinguish between statement and declaration This separates matching/parsing of statements and declarations and fixes a few edge cases where the parser would incorrectly accept a declaration where only a statement is allowed - for example: if (foo) const a = 1; for (var bar;;) function b() {} while (baz) class c {}
2020-10-22 22:30:07 +00:00
bool match_declaration() 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: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
void syntax_error(const String& message, Optional<Position> = {});
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: Unprefixed octal numbers are a syntax error in strict mode
2020-10-19 17:01:28 +00:00
Token consume_and_validate_numeric_literal();
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: Don't save rule start positions along with the parser state This fixes #4617. Also fixes the small problem where some save states would be leaked.
2020-12-29 13:17:39 +00:00
void discard_saved_state();
LibJS: Replace 'size_t line, size_t column' with 'Optional<Position>' This is a bit nicer for two reasons: - The absence of line number/column information isn't based on 'values are zero' anymore but on Optional's value - When reporting syntax errors with position information other than the current token's position we had to store line and column ourselves, like this: auto foo_start_line = m_parser_state.m_current_token.line_number(); auto foo_start_column = m_parser_state.m_current_token.line_column(); ... syntax_error("...", foo_start_line, foo_start_column); Which now becomes: auto foo_start= position(); ... syntax_error("...", foo_start); This makes it easier to report correct positions for syntax errors that only emerge a few tokens later :^)
2020-11-02 21:03:19 +00:00
Position position() 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
LibJS: Memoize failed calls of try_parse_arrow_function_expression()
2021-04-11 20:41:51 +00:00
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);
LibJS: Track source positions all the way down to exceptions This makes exceptions have a trace of source positions too, which could probably be helpful in making fancier error tracebacks.
2020-12-28 17:15:22 +00:00
struct RulePosition {
LibJS: `save_state()' before creating a RulePosition Fixes #4617.
2020-12-29 05:12:02 +00:00
AK_MAKE_NONCOPYABLE(RulePosition);
AK_MAKE_NONMOVABLE(RulePosition);
public:
LibJS: Track source positions all the way down to exceptions This makes exceptions have a trace of source positions too, which could probably be helpful in making fancier error tracebacks.
2020-12-28 17:15:22 +00:00
RulePosition(Parser& parser, Position position)
: m_parser(parser)
, m_position(position)
{
LibJS: Don't save rule start positions along with the parser state This fixes #4617. Also fixes the small problem where some save states would be leaked.
2020-12-29 13:17:39 +00:00
m_parser.m_rule_starts.append(position);
LibJS: Track source positions all the way down to exceptions This makes exceptions have a trace of source positions too, which could probably be helpful in making fancier error tracebacks.
2020-12-28 17:15:22 +00:00
}
~RulePosition()
{
LibJS: Don't save rule start positions along with the parser state This fixes #4617. Also fixes the small problem where some save states would be leaked.
2020-12-29 13:17:39 +00:00
auto last = m_parser.m_rule_starts.take_last();
Everywhere: Rename ASSERT => VERIFY (...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
2021-02-23 19:42:32 +00:00
VERIFY(last.line == m_position.line);
VERIFY(last.column == m_position.column);
LibJS: Track source positions all the way down to exceptions This makes exceptions have a trace of source positions too, which could probably be helpful in making fancier error tracebacks.
2020-12-28 17:15:22 +00:00
}
const Position& position() const { return m_position; }
private:
Parser& m_parser;
Position m_position;
};
[[nodiscard]] RulePosition push_start() { return { *this, position() }; }
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: 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: Implement 'new.target' This adds a new MetaProperty AST node which will be used for 'new.target' and 'import.meta' meta properties. The parser now distinguishes between "in function context" and "in arrow function context" (which is required for this). When encountering TokenType::New we will attempt to parse it as meta property and resort to regular new expression parsing if that fails, much like the parsing of labelled statements.
2020-11-02 21:27:42 +00:00
bool m_in_arrow_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: Support LegacyOctalEscapeSequence in string literals https://tc39.es/ecma262/#sec-additional-syntax-string-literals The syntax and semantics of 11.8.4 is extended as follows except that this extension is not allowed for strict mode code: Syntax EscapeSequence:: CharacterEscapeSequence LegacyOctalEscapeSequence NonOctalDecimalEscapeSequence HexEscapeSequence UnicodeEscapeSequence LegacyOctalEscapeSequence:: OctalDigit [lookahead ∉ OctalDigit] ZeroToThree OctalDigit [lookahead ∉ OctalDigit] FourToSeven OctalDigit ZeroToThree OctalDigit OctalDigit ZeroToThree :: one of 0 1 2 3 FourToSeven :: one of 4 5 6 7 NonOctalDecimalEscapeSequence :: one of 8 9 This definition of EscapeSequence is not used in strict mode or when parsing TemplateCharacter. Note It is possible for string literals to precede a Use Strict Directive that places the enclosing code in strict mode, and implementations must take care to not use this extended definition of EscapeSequence with such literals. For example, attempting to parse the following source text must fail: function invalid() { "\7"; "use strict"; }
2020-10-24 12:30:57 +00:00
bool m_string_legacy_octal_escape_sequence_in_scope { 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);
};
LibJS: Memoize failed calls of try_parse_arrow_function_expression()
2021-04-11 20:41:51 +00:00
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;
}
};
LibJS: Don't save rule start positions along with the parser state This fixes #4617. Also fixes the small problem where some save states would be leaked.
2020-12-29 13:17:39 +00:00
Vector<Position> m_rule_starts;
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
ParserState m_parser_state;
LibJS: Keep track of file names, lines and columns inside the AST
2021-02-28 09:42:34 +00:00
FlyString m_filename;
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: Memoize failed calls of try_parse_arrow_function_expression()
2021-04-11 20:41:51 +00:00
HashMap<Position, TokenMemoization, PositionKeyTraits> m_token_memoizations;
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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