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https://github.com/LadybirdBrowser/ladybird.git
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00182a2405
This ports the lexer to UTF-16 and deals with the immediate fallout up to the AST. The AST will be dealt with in upcoming commits. The lexer will still accept UTF-8 strings as input, and will transcode them to UTF-16 for lexing. This doesn't actually incur a new allocation, as we were already converting the input StringView to a ByteString for each lexer. One immediate logical benefit here is that we do not need to know off- hand how many UTF-8 bytes some special code points occupy. They all happen to be a single UTF-16 code unit. So instead of advancing the lexer by 3 positions in some cases, we can just always advance by 1.
95 lines
2.8 KiB
C++
95 lines
2.8 KiB
C++
/*
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* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/HashMap.h>
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#include <AK/StringView.h>
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#include <AK/Utf16String.h>
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#include <LibJS/Export.h>
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#include <LibJS/Token.h>
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namespace JS {
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class JS_API Lexer {
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public:
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explicit Lexer(StringView source, StringView filename = "(unknown)"sv, size_t line_number = 1, size_t line_column = 0);
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explicit Lexer(Utf16String source, StringView filename = "(unknown)"sv, size_t line_number = 1, size_t line_column = 0);
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Token next();
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Utf16String const& source() const { return m_source; }
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String const& filename() const { return m_filename; }
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void disallow_html_comments() { m_allow_html_comments = false; }
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Token force_slash_as_regex();
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private:
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void consume();
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bool consume_exponent();
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bool consume_octal_number();
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bool consume_hexadecimal_number();
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bool consume_binary_number();
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bool consume_decimal_number();
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u32 current_code_point() const;
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bool is_eof() const;
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bool is_line_terminator() const;
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bool is_whitespace() const;
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Optional<u32> is_identifier_unicode_escape(size_t& identifier_length) const;
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Optional<u32> is_identifier_start(size_t& identifier_length) const;
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Optional<u32> is_identifier_middle(size_t& identifier_length) const;
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bool is_line_comment_start(bool line_has_token_yet) const;
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bool is_block_comment_start() const;
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bool is_block_comment_end() const;
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bool is_numeric_literal_start() const;
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bool match(char16_t, char16_t) const;
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bool match(char16_t, char16_t, char16_t) const;
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bool match(char16_t, char16_t, char16_t, char16_t) const;
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template<typename Callback>
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bool match_numeric_literal_separator_followed_by(Callback) const;
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bool slash_means_division() const;
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TokenType consume_regex_literal();
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Utf16String m_source;
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size_t m_position { 0 };
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Token m_current_token;
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char16_t m_current_code_unit { 0 };
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bool m_eof { false };
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String m_filename;
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size_t m_line_number { 1 };
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size_t m_line_column { 0 };
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bool m_regex_is_in_character_class { false };
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struct TemplateState {
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bool in_expr;
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u8 open_bracket_count;
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};
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Vector<TemplateState> m_template_states;
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bool m_allow_html_comments { true };
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static HashMap<Utf16FlyString, TokenType> s_keywords;
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struct ParsedIdentifiers : public RefCounted<ParsedIdentifiers> {
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// Resolved identifiers must be kept alive for the duration of the parsing stage, otherwise
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// the only references to these strings are deleted by the Token destructor.
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HashTable<Utf16FlyString> identifiers;
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};
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RefPtr<ParsedIdentifiers> m_parsed_identifiers;
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};
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bool is_syntax_character(u32 code_point);
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bool is_whitespace(u32 code_point);
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bool is_line_terminator(u32 code_point);
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}
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