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LibJS: Add a mode to parse JS as a module

In a module strict mode should be enabled at the start of parsing and we
allow import and export statements.
This commit is contained in:
davidot 2021-08-14 17:30:37 +02:00 committed by Linus Groh
parent d6d7d11590
commit 7613c22b06
8 changed files with 38 additions and 15 deletions

View file

@ -168,8 +168,14 @@ private:
class Program final : public ScopeNode {
public:
explicit Program(SourceRange source_range)
enum class Type {
Script,
Module
};
explicit Program(SourceRange source_range, Type program_type)
: ScopeNode(source_range)
, m_type(program_type)
{
}
@ -178,10 +184,13 @@ public:
bool is_strict_mode() const { return m_is_strict_mode; }
void set_strict_mode() { m_is_strict_mode = true; }
Type type() const { return m_type; }
private:
virtual bool is_program() const override { return true; }
bool m_is_strict_mode { false };
Type m_type { Type::Script };
};
class BlockStatement final : public ScopeNode {

View file

@ -330,11 +330,11 @@ bool Lexer::is_identifier_middle() const
bool Lexer::is_line_comment_start(bool line_has_token_yet) const
{
return match('/', '/')
|| match('<', '!', '-', '-')
|| (m_allow_html_comments && match('<', '!', '-', '-'))
// "-->" is considered a line comment start if the current line is only whitespace and/or
// other block comment(s); or in other words: the current line does not have a token or
// ongoing line comment yet
|| (match('-', '-', '>') && !line_has_token_yet)
|| (m_allow_html_comments && !line_has_token_yet && match('-', '-', '>'))
// https://tc39.es/proposal-hashbang/out.html#sec-updated-syntax
|| (match('#', '!') && m_position == 1);
}

View file

@ -23,6 +23,8 @@ public:
const StringView& source() const { return m_source; };
const StringView& filename() const { return m_filename; };
void disallow_html_comments() { m_allow_html_comments = false; };
private:
void consume();
bool consume_exponent();
@ -63,6 +65,8 @@ private:
};
Vector<TemplateState> m_template_states;
bool m_allow_html_comments { true };
static HashMap<String, TokenType> s_keywords;
static HashMap<String, TokenType> s_three_char_tokens;
static HashMap<String, TokenType> s_two_char_tokens;

View file

@ -208,10 +208,13 @@ private:
constexpr OperatorPrecedenceTable g_operator_precedence;
Parser::ParserState::ParserState(Lexer l)
Parser::ParserState::ParserState(Lexer l, Program::Type program_type)
: lexer(move(l))
, current_token(lexer.next())
, current_token(TokenType::Invalid, {}, {}, {}, {}, 0, 0, 0)
{
if (program_type == Program::Type::Module)
lexer.disallow_html_comments();
current_token = lexer.next();
}
Parser::Scope::Scope(Parser::Scope::Type type, RefPtr<Parser::Scope> parent_scope)
@ -232,8 +235,9 @@ RefPtr<Parser::Scope> Parser::Scope::get_current_function_scope()
return result;
}
Parser::Parser(Lexer lexer)
: m_state(move(lexer))
Parser::Parser(Lexer lexer, Program::Type program_type)
: m_state(move(lexer), program_type)
, m_program_type(program_type)
{
}
@ -282,8 +286,8 @@ NonnullRefPtr<Program> Parser::parse_program(bool starts_in_strict_mode)
{
auto rule_start = push_start();
ScopePusher scope(*this, ScopePusher::Var | ScopePusher::Let, Scope::Function);
auto program = adopt_ref(*new Program({ m_filename, rule_start.position(), position() }));
if (starts_in_strict_mode) {
auto program = adopt_ref(*new Program({ m_filename, rule_start.position(), position() }, m_program_type));
if (starts_in_strict_mode || m_program_type == Program::Type::Module) {
program->set_strict_mode();
m_state.strict_mode = true;
}

View file

@ -35,7 +35,7 @@ struct FunctionNodeParseOptions {
class Parser {
public:
explicit Parser(Lexer lexer);
explicit Parser(Lexer lexer, Program::Type program_type = Program::Type::Script);
NonnullRefPtr<Program> parse_program(bool starts_in_strict_mode = false);
@ -246,7 +246,7 @@ private:
bool in_continue_context { false };
bool string_legacy_octal_escape_sequence_in_scope { false };
explicit ParserState(Lexer);
ParserState(Lexer, Program::Type);
};
class PositionKeyTraits {
@ -267,5 +267,6 @@ private:
FlyString m_filename;
Vector<ParserState> m_saved_state;
HashMap<Position, TokenMemoization, PositionKeyTraits> m_token_memoizations;
Program::Type m_program_type;
};
}