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	 e2e7c4d574
			
		
	
	
		e2e7c4d574
		
	
	
	
	
		
			
			In a bunch of cases, this actually ends up simplifying the code as
to_number will handle something such as:
```
Optional<I> opt;
if constexpr (IsSigned<I>)
    opt = view.to_int<I>();
else
    opt = view.to_uint<I>();
```
For us.
The main goal here however is to have a single generic number conversion
API between all of the String classes.
		
	
			
		
			
				
	
	
		
			973 lines
		
	
	
	
		
			40 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			973 lines
		
	
	
	
		
			40 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
 | ||
|  * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
 | ||
|  * Copyright (c) 2020-2021, the SerenityOS developers.
 | ||
|  * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
 | ||
|  * Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
 | ||
|  * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
 | ||
|  *
 | ||
|  * SPDX-License-Identifier: BSD-2-Clause
 | ||
|  */
 | ||
| 
 | ||
| #include <AK/Debug.h>
 | ||
| #include <LibWeb/CSS/Parser/Parser.h>
 | ||
| #include <LibWeb/Infra/Strings.h>
 | ||
| 
 | ||
| namespace Web::CSS::Parser {
 | ||
| 
 | ||
| Optional<SelectorList> Parser::parse_as_selector(SelectorParsingMode parsing_mode)
 | ||
| {
 | ||
|     auto selector_list = parse_a_selector_list(m_token_stream, SelectorType::Standalone, parsing_mode);
 | ||
|     if (!selector_list.is_error())
 | ||
|         return selector_list.release_value();
 | ||
| 
 | ||
|     return {};
 | ||
| }
 | ||
| 
 | ||
| Optional<SelectorList> Parser::parse_as_relative_selector(SelectorParsingMode parsing_mode)
 | ||
| {
 | ||
|     auto selector_list = parse_a_selector_list(m_token_stream, SelectorType::Relative, parsing_mode);
 | ||
|     if (!selector_list.is_error())
 | ||
|         return selector_list.release_value();
 | ||
| 
 | ||
|     return {};
 | ||
| }
 | ||
| 
 | ||
| template<typename T>
 | ||
| Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<T>& tokens, SelectorType mode, SelectorParsingMode parsing_mode)
 | ||
| {
 | ||
|     auto comma_separated_lists = parse_a_comma_separated_list_of_component_values(tokens);
 | ||
| 
 | ||
|     Vector<NonnullRefPtr<Selector>> selectors;
 | ||
|     for (auto& selector_parts : comma_separated_lists) {
 | ||
|         auto stream = TokenStream(selector_parts);
 | ||
|         auto selector = parse_complex_selector(stream, mode);
 | ||
|         if (selector.is_error()) {
 | ||
|             if (parsing_mode == SelectorParsingMode::Forgiving)
 | ||
|                 continue;
 | ||
|             return selector.error();
 | ||
|         }
 | ||
|         selectors.append(selector.release_value());
 | ||
|     }
 | ||
| 
 | ||
|     if (selectors.is_empty() && parsing_mode != SelectorParsingMode::Forgiving)
 | ||
|         return ParseError::SyntaxError;
 | ||
| 
 | ||
|     return selectors;
 | ||
| }
 | ||
| template Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<ComponentValue>&, SelectorType, SelectorParsingMode);
 | ||
| template Parser::ParseErrorOr<SelectorList> Parser::parse_a_selector_list(TokenStream<Token>&, SelectorType, SelectorParsingMode);
 | ||
| 
 | ||
| Parser::ParseErrorOr<NonnullRefPtr<Selector>> Parser::parse_complex_selector(TokenStream<ComponentValue>& tokens, SelectorType mode)
 | ||
| {
 | ||
|     Vector<Selector::CompoundSelector> compound_selectors;
 | ||
| 
 | ||
|     auto first_selector = TRY(parse_compound_selector(tokens));
 | ||
|     if (!first_selector.has_value())
 | ||
|         return ParseError::SyntaxError;
 | ||
| 
 | ||
|     if (mode == SelectorType::Standalone) {
 | ||
|         if (first_selector->combinator != Selector::Combinator::Descendant)
 | ||
|             return ParseError::SyntaxError;
 | ||
|         first_selector->combinator = Selector::Combinator::None;
 | ||
|     }
 | ||
|     compound_selectors.append(first_selector.release_value());
 | ||
| 
 | ||
|     while (tokens.has_next_token()) {
 | ||
|         auto compound_selector = TRY(parse_compound_selector(tokens));
 | ||
|         if (!compound_selector.has_value())
 | ||
|             break;
 | ||
|         compound_selectors.append(compound_selector.release_value());
 | ||
|     }
 | ||
| 
 | ||
|     if (compound_selectors.is_empty())
 | ||
|         return ParseError::SyntaxError;
 | ||
| 
 | ||
|     return Selector::create(move(compound_selectors));
 | ||
| }
 | ||
| 
 | ||
| Parser::ParseErrorOr<Optional<Selector::CompoundSelector>> Parser::parse_compound_selector(TokenStream<ComponentValue>& tokens)
 | ||
| {
 | ||
|     tokens.skip_whitespace();
 | ||
| 
 | ||
|     auto combinator = parse_selector_combinator(tokens).value_or(Selector::Combinator::Descendant);
 | ||
| 
 | ||
|     tokens.skip_whitespace();
 | ||
| 
 | ||
|     Vector<Selector::SimpleSelector> simple_selectors;
 | ||
| 
 | ||
|     while (tokens.has_next_token()) {
 | ||
|         auto component = TRY(parse_simple_selector(tokens));
 | ||
|         if (!component.has_value())
 | ||
|             break;
 | ||
|         simple_selectors.append(component.release_value());
 | ||
|     }
 | ||
| 
 | ||
|     if (simple_selectors.is_empty())
 | ||
|         return Optional<Selector::CompoundSelector> {};
 | ||
| 
 | ||
|     return Selector::CompoundSelector { combinator, move(simple_selectors) };
 | ||
| }
 | ||
| 
 | ||
| Optional<Selector::Combinator> Parser::parse_selector_combinator(TokenStream<ComponentValue>& tokens)
 | ||
| {
 | ||
|     auto const& current_value = tokens.next_token();
 | ||
|     if (current_value.is(Token::Type::Delim)) {
 | ||
|         switch (current_value.token().delim()) {
 | ||
|         case '>':
 | ||
|             return Selector::Combinator::ImmediateChild;
 | ||
|         case '+':
 | ||
|             return Selector::Combinator::NextSibling;
 | ||
|         case '~':
 | ||
|             return Selector::Combinator::SubsequentSibling;
 | ||
|         case '|': {
 | ||
|             auto const& next = tokens.peek_token();
 | ||
|             if (next.is(Token::Type::EndOfFile))
 | ||
|                 return {};
 | ||
| 
 | ||
|             if (next.is_delim('|')) {
 | ||
|                 tokens.next_token();
 | ||
|                 return Selector::Combinator::Column;
 | ||
|             }
 | ||
|         }
 | ||
|         }
 | ||
|     }
 | ||
| 
 | ||
|     tokens.reconsume_current_input_token();
 | ||
|     return {};
 | ||
| }
 | ||
| 
 | ||
| Optional<Selector::SimpleSelector::QualifiedName> Parser::parse_selector_qualified_name(TokenStream<ComponentValue>& tokens, AllowWildcardName allow_wildcard_name)
 | ||
| {
 | ||
|     auto is_name = [](ComponentValue const& token) {
 | ||
|         return token.is_delim('*') || token.is(Token::Type::Ident);
 | ||
|     };
 | ||
|     auto get_name = [](ComponentValue const& token) {
 | ||
|         if (token.is_delim('*'))
 | ||
|             return "*"_fly_string;
 | ||
|         return token.token().ident();
 | ||
|     };
 | ||
| 
 | ||
|     // There are 3 possibilities here:
 | ||
|     // (Where <name> and <namespace> are either an <ident> or a `*` delim)
 | ||
|     // 1) `|<name>`
 | ||
|     // 2) `<namespace>|<name>`
 | ||
|     // 3) `<name>`
 | ||
|     // Whitespace is forbidden between any of these parts. https://www.w3.org/TR/selectors-4/#white-space
 | ||
| 
 | ||
|     auto transaction = tokens.begin_transaction();
 | ||
| 
 | ||
|     auto first_token = tokens.next_token();
 | ||
|     if (first_token.is_delim('|')) {
 | ||
|         // Case 1: `|<name>`
 | ||
|         if (is_name(tokens.peek_token())) {
 | ||
|             auto name_token = tokens.next_token();
 | ||
| 
 | ||
|             if (allow_wildcard_name == AllowWildcardName::No && name_token.is_delim('*'))
 | ||
|                 return {};
 | ||
| 
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::QualifiedName {
 | ||
|                 .namespace_type = Selector::SimpleSelector::QualifiedName::NamespaceType::None,
 | ||
|                 .name = get_name(name_token),
 | ||
|             };
 | ||
|         }
 | ||
|         return {};
 | ||
|     }
 | ||
| 
 | ||
|     if (!is_name(first_token))
 | ||
|         return {};
 | ||
| 
 | ||
|     if (tokens.peek_token().is_delim('|') && is_name(tokens.peek_token(1))) {
 | ||
|         // Case 2: `<namespace>|<name>`
 | ||
|         (void)tokens.next_token(); // `|`
 | ||
|         auto namespace_ = get_name(first_token);
 | ||
|         auto name = get_name(tokens.next_token());
 | ||
| 
 | ||
|         if (allow_wildcard_name == AllowWildcardName::No && name == "*"sv)
 | ||
|             return {};
 | ||
| 
 | ||
|         auto namespace_type = namespace_ == "*"sv
 | ||
|             ? Selector::SimpleSelector::QualifiedName::NamespaceType::Any
 | ||
|             : Selector::SimpleSelector::QualifiedName::NamespaceType::Named;
 | ||
| 
 | ||
|         transaction.commit();
 | ||
|         return Selector::SimpleSelector::QualifiedName {
 | ||
|             .namespace_type = namespace_type,
 | ||
|             .namespace_ = namespace_,
 | ||
|             .name = name,
 | ||
|         };
 | ||
|     }
 | ||
| 
 | ||
|     // Case 3: `<name>`
 | ||
|     auto& name_token = first_token;
 | ||
|     if (allow_wildcard_name == AllowWildcardName::No && name_token.is_delim('*'))
 | ||
|         return {};
 | ||
| 
 | ||
|     transaction.commit();
 | ||
|     return Selector::SimpleSelector::QualifiedName {
 | ||
|         .namespace_type = Selector::SimpleSelector::QualifiedName::NamespaceType::Default,
 | ||
|         .name = get_name(name_token),
 | ||
|     };
 | ||
| }
 | ||
| 
 | ||
| Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_attribute_simple_selector(ComponentValue const& first_value)
 | ||
| {
 | ||
|     auto attribute_tokens = TokenStream { first_value.block().values() };
 | ||
| 
 | ||
|     attribute_tokens.skip_whitespace();
 | ||
| 
 | ||
|     if (!attribute_tokens.has_next_token()) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "CSS attribute selector is empty!");
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     auto maybe_qualified_name = parse_selector_qualified_name(attribute_tokens, AllowWildcardName::No);
 | ||
|     if (!maybe_qualified_name.has_value()) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Expected qualified-name for attribute name, got: '{}'", attribute_tokens.peek_token().to_debug_string());
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     Selector::SimpleSelector simple_selector {
 | ||
|         .type = Selector::SimpleSelector::Type::Attribute,
 | ||
|         .value = Selector::SimpleSelector::Attribute {
 | ||
|             .match_type = Selector::SimpleSelector::Attribute::MatchType::HasAttribute,
 | ||
|             // FIXME: Case-sensitivity is defined by the document language.
 | ||
|             // HTML is insensitive with attribute names, and our code generally assumes
 | ||
|             // they are converted to lowercase, so we do that here too. If we want to be
 | ||
|             // correct with XML later, we'll need to keep the original case and then do
 | ||
|             // a case-insensitive compare later.
 | ||
|             .qualified_name = maybe_qualified_name.release_value(),
 | ||
|             .case_type = Selector::SimpleSelector::Attribute::CaseType::DefaultMatch,
 | ||
|         }
 | ||
|     };
 | ||
| 
 | ||
|     attribute_tokens.skip_whitespace();
 | ||
|     if (!attribute_tokens.has_next_token())
 | ||
|         return simple_selector;
 | ||
| 
 | ||
|     auto const& delim_part = attribute_tokens.next_token();
 | ||
|     if (!delim_part.is(Token::Type::Delim)) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Expected a delim for attribute comparison, got: '{}'", delim_part.to_debug_string());
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     if (delim_part.token().delim() == '=') {
 | ||
|         simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ExactValueMatch;
 | ||
|     } else {
 | ||
|         if (!attribute_tokens.has_next_token()) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Attribute selector ended part way through a match type.");
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
| 
 | ||
|         auto const& delim_second_part = attribute_tokens.next_token();
 | ||
|         if (!delim_second_part.is_delim('=')) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Expected a double delim for attribute comparison, got: '{}{}'", delim_part.to_debug_string(), delim_second_part.to_debug_string());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
|         switch (delim_part.token().delim()) {
 | ||
|         case '~':
 | ||
|             simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsWord;
 | ||
|             break;
 | ||
|         case '*':
 | ||
|             simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::ContainsString;
 | ||
|             break;
 | ||
|         case '|':
 | ||
|             simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithSegment;
 | ||
|             break;
 | ||
|         case '^':
 | ||
|             simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::StartsWithString;
 | ||
|             break;
 | ||
|         case '$':
 | ||
|             simple_selector.attribute().match_type = Selector::SimpleSelector::Attribute::MatchType::EndsWithString;
 | ||
|             break;
 | ||
|         default:
 | ||
|             attribute_tokens.reconsume_current_input_token();
 | ||
|         }
 | ||
|     }
 | ||
| 
 | ||
|     attribute_tokens.skip_whitespace();
 | ||
|     if (!attribute_tokens.has_next_token()) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Attribute selector ended without a value to match.");
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     auto const& value_part = attribute_tokens.next_token();
 | ||
|     if (!value_part.is(Token::Type::Ident) && !value_part.is(Token::Type::String)) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Expected a string or ident for the value to match attribute against, got: '{}'", value_part.to_debug_string());
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
|     auto const& value_string = value_part.token().is(Token::Type::Ident) ? value_part.token().ident() : value_part.token().string();
 | ||
|     simple_selector.attribute().value = value_string.to_string();
 | ||
| 
 | ||
|     attribute_tokens.skip_whitespace();
 | ||
|     // Handle case-sensitivity suffixes. https://www.w3.org/TR/selectors-4/#attribute-case
 | ||
|     if (attribute_tokens.has_next_token()) {
 | ||
|         auto const& case_sensitivity_part = attribute_tokens.next_token();
 | ||
|         if (case_sensitivity_part.is(Token::Type::Ident)) {
 | ||
|             auto case_sensitivity = case_sensitivity_part.token().ident();
 | ||
|             if (case_sensitivity.equals_ignoring_ascii_case("i"sv)) {
 | ||
|                 simple_selector.attribute().case_type = Selector::SimpleSelector::Attribute::CaseType::CaseInsensitiveMatch;
 | ||
|             } else if (case_sensitivity.equals_ignoring_ascii_case("s"sv)) {
 | ||
|                 simple_selector.attribute().case_type = Selector::SimpleSelector::Attribute::CaseType::CaseSensitiveMatch;
 | ||
|             } else {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Expected a \"i\" or \"s\" attribute selector case sensitivity identifier, got: '{}'", case_sensitivity_part.to_debug_string());
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
|         } else {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Expected an attribute selector case sensitivity identifier, got: '{}'", case_sensitivity_part.to_debug_string());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
|     }
 | ||
| 
 | ||
|     if (attribute_tokens.has_next_token()) {
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Was not expecting anything else inside attribute selector.");
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     return simple_selector;
 | ||
| }
 | ||
| 
 | ||
| Parser::ParseErrorOr<Selector::SimpleSelector> Parser::parse_pseudo_simple_selector(TokenStream<ComponentValue>& tokens)
 | ||
| {
 | ||
|     auto peek_token_ends_selector = [&]() -> bool {
 | ||
|         auto const& value = tokens.peek_token();
 | ||
|         return (value.is(Token::Type::EndOfFile) || value.is(Token::Type::Whitespace) || value.is(Token::Type::Comma));
 | ||
|     };
 | ||
| 
 | ||
|     if (peek_token_ends_selector())
 | ||
|         return ParseError::SyntaxError;
 | ||
| 
 | ||
|     bool is_pseudo = false;
 | ||
|     if (tokens.peek_token().is(Token::Type::Colon)) {
 | ||
|         is_pseudo = true;
 | ||
|         tokens.next_token();
 | ||
|         if (peek_token_ends_selector())
 | ||
|             return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     if (is_pseudo) {
 | ||
|         auto const& name_token = tokens.next_token();
 | ||
|         if (!name_token.is(Token::Type::Ident)) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Expected an ident for pseudo-element, got: '{}'", name_token.to_debug_string());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
| 
 | ||
|         auto pseudo_name = name_token.token().ident();
 | ||
| 
 | ||
|         // Note: We allow the "ignored" -webkit prefix here for -webkit-progress-bar/-webkit-progress-bar
 | ||
|         if (auto pseudo_element = Selector::PseudoElement::from_string(pseudo_name); pseudo_element.has_value()) {
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoElement,
 | ||
|                 .value = pseudo_element.release_value()
 | ||
|             };
 | ||
|         }
 | ||
| 
 | ||
|         // https://www.w3.org/TR/selectors-4/#compat
 | ||
|         // All other pseudo-elements whose names begin with the string “-webkit-” (matched ASCII case-insensitively)
 | ||
|         // and that are not functional notations must be treated as valid at parse time. (That is, ::-webkit-asdf is
 | ||
|         // valid at parse time, but ::-webkit-jkl() is not.) If they’re not otherwise recognized and supported, they
 | ||
|         // must be treated as matching nothing, and are unknown -webkit- pseudo-elements.
 | ||
|         if (pseudo_name.starts_with_bytes("-webkit-"sv, CaseSensitivity::CaseInsensitive)) {
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoElement,
 | ||
|                 // Unknown -webkit- pseudo-elements must be serialized in ASCII lowercase.
 | ||
|                 .value = Selector::PseudoElement { Selector::PseudoElement::Type::UnknownWebKit, MUST(Infra::to_ascii_lowercase(pseudo_name.to_string())) },
 | ||
|             };
 | ||
|         }
 | ||
| 
 | ||
|         if (has_ignored_vendor_prefix(pseudo_name))
 | ||
|             return ParseError::IncludesIgnoredVendorPrefix;
 | ||
| 
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-element: '::{}'", pseudo_name);
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     if (peek_token_ends_selector())
 | ||
|         return ParseError::SyntaxError;
 | ||
| 
 | ||
|     auto const& pseudo_class_token = tokens.next_token();
 | ||
| 
 | ||
|     if (pseudo_class_token.is(Token::Type::Ident)) {
 | ||
|         auto pseudo_name = pseudo_class_token.token().ident();
 | ||
|         if (has_ignored_vendor_prefix(pseudo_name))
 | ||
|             return ParseError::IncludesIgnoredVendorPrefix;
 | ||
| 
 | ||
|         auto make_pseudo_class_selector = [](auto pseudo_class) {
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector { .type = pseudo_class }
 | ||
|             };
 | ||
|         };
 | ||
| 
 | ||
|         if (auto pseudo_class = pseudo_class_from_string(pseudo_name); pseudo_class.has_value()) {
 | ||
|             if (!pseudo_class_metadata(pseudo_class.value()).is_valid_as_identifier) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Pseudo-class ':{}' is only valid as a function", pseudo_name);
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
|             return make_pseudo_class_selector(pseudo_class.value());
 | ||
|         }
 | ||
| 
 | ||
|         // Single-colon syntax allowed for ::after, ::before, ::first-letter and ::first-line for compatibility.
 | ||
|         // https://www.w3.org/TR/selectors/#pseudo-element-syntax
 | ||
|         if (auto pseudo_element = Selector::PseudoElement::from_string(pseudo_name); pseudo_element.has_value()) {
 | ||
|             switch (pseudo_element.value().type()) {
 | ||
|             case Selector::PseudoElement::Type::After:
 | ||
|             case Selector::PseudoElement::Type::Before:
 | ||
|             case Selector::PseudoElement::Type::FirstLetter:
 | ||
|             case Selector::PseudoElement::Type::FirstLine:
 | ||
|                 return Selector::SimpleSelector {
 | ||
|                     .type = Selector::SimpleSelector::Type::PseudoElement,
 | ||
|                     .value = pseudo_element.value()
 | ||
|                 };
 | ||
|             default:
 | ||
|                 break;
 | ||
|             }
 | ||
|         }
 | ||
| 
 | ||
|         dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-class: ':{}'", pseudo_name);
 | ||
|         return ParseError::SyntaxError;
 | ||
|     }
 | ||
| 
 | ||
|     if (pseudo_class_token.is_function()) {
 | ||
|         auto parse_nth_child_selector = [this](auto pseudo_class, Vector<ComponentValue> const& function_values, bool allow_of = false) -> ParseErrorOr<Selector::SimpleSelector> {
 | ||
|             auto tokens = TokenStream<ComponentValue>(function_values);
 | ||
|             auto nth_child_pattern = parse_a_n_plus_b_pattern(tokens);
 | ||
|             if (!nth_child_pattern.has_value()) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid An+B format for {}", pseudo_class_name(pseudo_class));
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
| 
 | ||
|             tokens.skip_whitespace();
 | ||
|             if (!tokens.has_next_token()) {
 | ||
|                 return Selector::SimpleSelector {
 | ||
|                     .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                     .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                         .type = pseudo_class,
 | ||
|                         .nth_child_pattern = nth_child_pattern.release_value() }
 | ||
|                 };
 | ||
|             }
 | ||
| 
 | ||
|             if (!allow_of)
 | ||
|                 return ParseError::SyntaxError;
 | ||
| 
 | ||
|             // Parse the `of <selector-list>` syntax
 | ||
|             auto const& maybe_of = tokens.next_token();
 | ||
|             if (!maybe_of.is_ident("of"sv))
 | ||
|                 return ParseError::SyntaxError;
 | ||
| 
 | ||
|             tokens.skip_whitespace();
 | ||
|             auto selector_list = TRY(parse_a_selector_list(tokens, SelectorType::Standalone));
 | ||
| 
 | ||
|             tokens.skip_whitespace();
 | ||
|             if (tokens.has_next_token())
 | ||
|                 return ParseError::SyntaxError;
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .nth_child_pattern = nth_child_pattern.release_value(),
 | ||
|                     .argument_selector_list = move(selector_list) }
 | ||
|             };
 | ||
|         };
 | ||
| 
 | ||
|         auto const& pseudo_function = pseudo_class_token.function();
 | ||
|         auto maybe_pseudo_class = pseudo_class_from_string(pseudo_function.name());
 | ||
|         if (!maybe_pseudo_class.has_value()) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Unrecognized pseudo-class function: ':{}'()", pseudo_function.name());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
|         auto pseudo_class = maybe_pseudo_class.value();
 | ||
|         auto metadata = pseudo_class_metadata(pseudo_class);
 | ||
| 
 | ||
|         if (!metadata.is_valid_as_function) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Pseudo-class ':{}' is not valid as a function", pseudo_function.name());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
| 
 | ||
|         if (pseudo_function.values().is_empty()) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Empty :{}() selector", pseudo_function.name());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
| 
 | ||
|         switch (metadata.parameter_type) {
 | ||
|         case PseudoClassMetadata::ParameterType::ANPlusB:
 | ||
|             return parse_nth_child_selector(pseudo_class, pseudo_function.values(), false);
 | ||
|         case PseudoClassMetadata::ParameterType::ANPlusBOf:
 | ||
|             return parse_nth_child_selector(pseudo_class, pseudo_function.values(), true);
 | ||
|         case PseudoClassMetadata::ParameterType::CompoundSelector: {
 | ||
|             auto function_token_stream = TokenStream(pseudo_function.values());
 | ||
|             auto compound_selector_or_error = parse_compound_selector(function_token_stream);
 | ||
|             if (compound_selector_or_error.is_error() || !compound_selector_or_error.value().has_value()) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as a compound selector", pseudo_function.name());
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
| 
 | ||
|             Vector compound_selectors { compound_selector_or_error.release_value().release_value() };
 | ||
|             auto selector = Selector::create(move(compound_selectors));
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .argument_selector_list = { move(selector) } }
 | ||
|             };
 | ||
|         }
 | ||
|         case PseudoClassMetadata::ParameterType::ForgivingSelectorList: {
 | ||
|             auto function_token_stream = TokenStream(pseudo_function.values());
 | ||
|             // NOTE: Because it's forgiving, even complete garbage will parse OK as an empty selector-list.
 | ||
|             auto argument_selector_list = MUST(parse_a_selector_list(function_token_stream, SelectorType::Standalone, SelectorParsingMode::Forgiving));
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .argument_selector_list = move(argument_selector_list) }
 | ||
|             };
 | ||
|         }
 | ||
|         case PseudoClassMetadata::ParameterType::Ident: {
 | ||
|             auto function_token_stream = TokenStream(pseudo_function.values());
 | ||
|             function_token_stream.skip_whitespace();
 | ||
|             auto maybe_ident_token = function_token_stream.next_token();
 | ||
|             function_token_stream.skip_whitespace();
 | ||
|             if (!maybe_ident_token.is(Token::Type::Ident) || function_token_stream.has_next_token()) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as an ident: not an ident", pseudo_function.name());
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
| 
 | ||
|             auto maybe_ident = value_id_from_string(maybe_ident_token.token().ident());
 | ||
|             if (!maybe_ident.has_value()) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Failed to parse :{}() parameter as an ident: unrecognized ident", pseudo_function.name());
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .identifier = maybe_ident.value() }
 | ||
|             };
 | ||
|         }
 | ||
|         case PseudoClassMetadata::ParameterType::LanguageRanges: {
 | ||
|             Vector<FlyString> languages;
 | ||
|             auto function_token_stream = TokenStream(pseudo_function.values());
 | ||
|             auto language_token_lists = parse_a_comma_separated_list_of_component_values(function_token_stream);
 | ||
| 
 | ||
|             for (auto language_token_list : language_token_lists) {
 | ||
|                 auto language_token_stream = TokenStream(language_token_list);
 | ||
|                 language_token_stream.skip_whitespace();
 | ||
|                 auto language_token = language_token_stream.next_token();
 | ||
|                 if (!(language_token.is(Token::Type::Ident) || language_token.is(Token::Type::String))) {
 | ||
|                     dbgln_if(CSS_PARSER_DEBUG, "Invalid language range in :{}() - not a string/ident", pseudo_function.name());
 | ||
|                     return ParseError::SyntaxError;
 | ||
|                 }
 | ||
| 
 | ||
|                 auto language_string = language_token.is(Token::Type::String) ? language_token.token().string() : language_token.token().ident();
 | ||
|                 languages.append(language_string);
 | ||
| 
 | ||
|                 language_token_stream.skip_whitespace();
 | ||
|                 if (language_token_stream.has_next_token()) {
 | ||
|                     dbgln_if(CSS_PARSER_DEBUG, "Invalid language range in :{}() - trailing tokens", pseudo_function.name());
 | ||
|                     return ParseError::SyntaxError;
 | ||
|                 }
 | ||
|             }
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .languages = move(languages) }
 | ||
|             };
 | ||
|         }
 | ||
|         case PseudoClassMetadata::ParameterType::SelectorList: {
 | ||
|             auto function_token_stream = TokenStream(pseudo_function.values());
 | ||
|             auto not_selector = TRY(parse_a_selector_list(function_token_stream, SelectorType::Standalone));
 | ||
| 
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::PseudoClass,
 | ||
|                 .value = Selector::SimpleSelector::PseudoClassSelector {
 | ||
|                     .type = pseudo_class,
 | ||
|                     .argument_selector_list = move(not_selector) }
 | ||
|             };
 | ||
|         }
 | ||
|         case PseudoClassMetadata::ParameterType::None:
 | ||
|             // `None` means this is not a function-type pseudo-class, so this state should be impossible.
 | ||
|             VERIFY_NOT_REACHED();
 | ||
|         }
 | ||
|     }
 | ||
|     dbgln_if(CSS_PARSER_DEBUG, "Unexpected Block in pseudo-class name, expected a function or identifier. '{}'", pseudo_class_token.to_debug_string());
 | ||
|     return ParseError::SyntaxError;
 | ||
| }
 | ||
| 
 | ||
| Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_selector(TokenStream<ComponentValue>& tokens)
 | ||
| {
 | ||
|     auto peek_token_ends_selector = [&]() -> bool {
 | ||
|         auto const& value = tokens.peek_token();
 | ||
|         return (value.is(Token::Type::EndOfFile) || value.is(Token::Type::Whitespace) || value.is(Token::Type::Comma));
 | ||
|     };
 | ||
| 
 | ||
|     if (peek_token_ends_selector())
 | ||
|         return Optional<Selector::SimpleSelector> {};
 | ||
| 
 | ||
|     // Handle universal and tag-name types together, since both can be namespaced
 | ||
|     if (auto qualified_name = parse_selector_qualified_name(tokens, AllowWildcardName::Yes); qualified_name.has_value()) {
 | ||
|         if (qualified_name->name.name == "*"sv) {
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::Universal,
 | ||
|                 .value = qualified_name.release_value(),
 | ||
|             };
 | ||
|         }
 | ||
|         return Selector::SimpleSelector {
 | ||
|             .type = Selector::SimpleSelector::Type::TagName,
 | ||
|             .value = qualified_name.release_value(),
 | ||
|         };
 | ||
|     }
 | ||
| 
 | ||
|     auto const& first_value = tokens.next_token();
 | ||
| 
 | ||
|     if (first_value.is(Token::Type::Delim)) {
 | ||
|         u32 delim = first_value.token().delim();
 | ||
|         switch (delim) {
 | ||
|         case '*':
 | ||
|             // Handled already
 | ||
|             VERIFY_NOT_REACHED();
 | ||
|         case '.': {
 | ||
|             if (peek_token_ends_selector())
 | ||
|                 return ParseError::SyntaxError;
 | ||
| 
 | ||
|             auto const& class_name_value = tokens.next_token();
 | ||
|             if (!class_name_value.is(Token::Type::Ident)) {
 | ||
|                 dbgln_if(CSS_PARSER_DEBUG, "Expected an ident after '.', got: {}", class_name_value.to_debug_string());
 | ||
|                 return ParseError::SyntaxError;
 | ||
|             }
 | ||
|             return Selector::SimpleSelector {
 | ||
|                 .type = Selector::SimpleSelector::Type::Class,
 | ||
|                 .value = Selector::SimpleSelector::Name { class_name_value.token().ident() }
 | ||
|             };
 | ||
|         }
 | ||
|         case '>':
 | ||
|         case '+':
 | ||
|         case '~':
 | ||
|         case '|':
 | ||
|             // Whitespace is not required between the compound-selector and a combinator.
 | ||
|             // So, if we see a combinator, return that this compound-selector is done, instead of a syntax error.
 | ||
|             tokens.reconsume_current_input_token();
 | ||
|             return Optional<Selector::SimpleSelector> {};
 | ||
|         default:
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid simple selector!");
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
|     }
 | ||
| 
 | ||
|     if (first_value.is(Token::Type::Hash)) {
 | ||
|         if (first_value.token().hash_type() != Token::HashType::Id) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Selector contains hash token that is not an id: {}", first_value.to_debug_string());
 | ||
|             return ParseError::SyntaxError;
 | ||
|         }
 | ||
|         return Selector::SimpleSelector {
 | ||
|             .type = Selector::SimpleSelector::Type::Id,
 | ||
|             .value = Selector::SimpleSelector::Name { first_value.token().hash_value() }
 | ||
|         };
 | ||
|     }
 | ||
| 
 | ||
|     if (first_value.is_block() && first_value.block().is_square())
 | ||
|         return TRY(parse_attribute_simple_selector(first_value));
 | ||
| 
 | ||
|     if (first_value.is(Token::Type::Colon))
 | ||
|         return TRY(parse_pseudo_simple_selector(tokens));
 | ||
| 
 | ||
|     dbgln_if(CSS_PARSER_DEBUG, "!!! Invalid simple selector!");
 | ||
|     return ParseError::SyntaxError;
 | ||
| }
 | ||
| 
 | ||
| Optional<Selector::SimpleSelector::ANPlusBPattern> Parser::parse_a_n_plus_b_pattern(TokenStream<ComponentValue>& values)
 | ||
| {
 | ||
|     auto transaction = values.begin_transaction();
 | ||
|     auto syntax_error = [&]() -> Optional<Selector::SimpleSelector::ANPlusBPattern> {
 | ||
|         if constexpr (CSS_PARSER_DEBUG) {
 | ||
|             dbgln_if(CSS_PARSER_DEBUG, "Invalid An+B value:");
 | ||
|             values.dump_all_tokens();
 | ||
|         }
 | ||
|         return {};
 | ||
|     };
 | ||
| 
 | ||
|     auto is_sign = [](ComponentValue const& value) -> bool {
 | ||
|         return value.is(Token::Type::Delim) && (value.token().delim() == '+' || value.token().delim() == '-');
 | ||
|     };
 | ||
|     auto is_n_dimension = [](ComponentValue const& value) -> bool {
 | ||
|         if (!value.is(Token::Type::Dimension))
 | ||
|             return false;
 | ||
|         if (!value.token().number().is_integer())
 | ||
|             return false;
 | ||
|         if (!value.token().dimension_unit().equals_ignoring_ascii_case("n"sv))
 | ||
|             return false;
 | ||
|         return true;
 | ||
|     };
 | ||
|     auto is_ndash_dimension = [](ComponentValue const& value) -> bool {
 | ||
|         if (!value.is(Token::Type::Dimension))
 | ||
|             return false;
 | ||
|         if (!value.token().number().is_integer())
 | ||
|             return false;
 | ||
|         if (!value.token().dimension_unit().equals_ignoring_ascii_case("n-"sv))
 | ||
|             return false;
 | ||
|         return true;
 | ||
|     };
 | ||
|     auto is_ndashdigit_dimension = [](ComponentValue const& value) -> bool {
 | ||
|         if (!value.is(Token::Type::Dimension))
 | ||
|             return false;
 | ||
|         if (!value.token().number().is_integer())
 | ||
|             return false;
 | ||
|         auto dimension_unit = value.token().dimension_unit();
 | ||
|         if (!dimension_unit.starts_with_bytes("n-"sv, CaseSensitivity::CaseInsensitive))
 | ||
|             return false;
 | ||
|         for (size_t i = 2; i < dimension_unit.bytes_as_string_view().length(); ++i) {
 | ||
|             if (!is_ascii_digit(dimension_unit.bytes_as_string_view()[i]))
 | ||
|                 return false;
 | ||
|         }
 | ||
|         return true;
 | ||
|     };
 | ||
|     auto is_ndashdigit_ident = [](ComponentValue const& value) -> bool {
 | ||
|         if (!value.is(Token::Type::Ident))
 | ||
|             return false;
 | ||
|         auto ident = value.token().ident();
 | ||
|         if (!ident.starts_with_bytes("n-"sv, CaseSensitivity::CaseInsensitive))
 | ||
|             return false;
 | ||
|         for (size_t i = 2; i < ident.bytes_as_string_view().length(); ++i) {
 | ||
|             if (!is_ascii_digit(ident.bytes_as_string_view()[i]))
 | ||
|                 return false;
 | ||
|         }
 | ||
|         return true;
 | ||
|     };
 | ||
|     auto is_dashndashdigit_ident = [](ComponentValue const& value) -> bool {
 | ||
|         if (!value.is(Token::Type::Ident))
 | ||
|             return false;
 | ||
|         auto ident = value.token().ident();
 | ||
|         if (!ident.starts_with_bytes("-n-"sv, CaseSensitivity::CaseInsensitive))
 | ||
|             return false;
 | ||
|         if (ident.bytes_as_string_view().length() == 3)
 | ||
|             return false;
 | ||
|         for (size_t i = 3; i < ident.bytes_as_string_view().length(); ++i) {
 | ||
|             if (!is_ascii_digit(ident.bytes_as_string_view()[i]))
 | ||
|                 return false;
 | ||
|         }
 | ||
|         return true;
 | ||
|     };
 | ||
|     auto is_integer = [](ComponentValue const& value) -> bool {
 | ||
|         return value.is(Token::Type::Number) && value.token().number().is_integer();
 | ||
|     };
 | ||
|     auto is_signed_integer = [](ComponentValue const& value) -> bool {
 | ||
|         return value.is(Token::Type::Number) && value.token().number().is_integer_with_explicit_sign();
 | ||
|     };
 | ||
|     auto is_signless_integer = [](ComponentValue const& value) -> bool {
 | ||
|         return value.is(Token::Type::Number) && !value.token().number().is_integer_with_explicit_sign();
 | ||
|     };
 | ||
| 
 | ||
|     // https://www.w3.org/TR/css-syntax-3/#the-anb-type
 | ||
|     // Unfortunately these can't be in the same order as in the spec.
 | ||
| 
 | ||
|     values.skip_whitespace();
 | ||
|     auto const& first_value = values.next_token();
 | ||
| 
 | ||
|     // odd | even
 | ||
|     if (first_value.is(Token::Type::Ident)) {
 | ||
|         auto ident = first_value.token().ident();
 | ||
|         if (ident.equals_ignoring_ascii_case("odd"sv)) {
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { 2, 1 };
 | ||
|         }
 | ||
|         if (ident.equals_ignoring_ascii_case("even"sv)) {
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { 2, 0 };
 | ||
|         }
 | ||
|     }
 | ||
|     // <integer>
 | ||
|     if (is_integer(first_value)) {
 | ||
|         int b = first_value.token().to_integer();
 | ||
|         transaction.commit();
 | ||
|         return Selector::SimpleSelector::ANPlusBPattern { 0, b };
 | ||
|     }
 | ||
|     // <n-dimension>
 | ||
|     // <n-dimension> <signed-integer>
 | ||
|     // <n-dimension> ['+' | '-'] <signless-integer>
 | ||
|     if (is_n_dimension(first_value)) {
 | ||
|         int a = first_value.token().dimension_value_int();
 | ||
|         values.skip_whitespace();
 | ||
| 
 | ||
|         // <n-dimension> <signed-integer>
 | ||
|         if (is_signed_integer(values.peek_token())) {
 | ||
|             int b = values.next_token().token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { a, b };
 | ||
|         }
 | ||
| 
 | ||
|         // <n-dimension> ['+' | '-'] <signless-integer>
 | ||
|         {
 | ||
|             auto child_transaction = transaction.create_child();
 | ||
|             auto const& second_value = values.next_token();
 | ||
|             values.skip_whitespace();
 | ||
|             auto const& third_value = values.next_token();
 | ||
| 
 | ||
|             if (is_sign(second_value) && is_signless_integer(third_value)) {
 | ||
|                 int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
 | ||
|                 child_transaction.commit();
 | ||
|                 return Selector::SimpleSelector::ANPlusBPattern { a, b };
 | ||
|             }
 | ||
|         }
 | ||
| 
 | ||
|         // <n-dimension>
 | ||
|         transaction.commit();
 | ||
|         return Selector::SimpleSelector::ANPlusBPattern { a, 0 };
 | ||
|     }
 | ||
|     // <ndash-dimension> <signless-integer>
 | ||
|     if (is_ndash_dimension(first_value)) {
 | ||
|         values.skip_whitespace();
 | ||
|         auto const& second_value = values.next_token();
 | ||
|         if (is_signless_integer(second_value)) {
 | ||
|             int a = first_value.token().dimension_value_int();
 | ||
|             int b = -second_value.token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { a, b };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
|     // <ndashdigit-dimension>
 | ||
|     if (is_ndashdigit_dimension(first_value)) {
 | ||
|         auto const& dimension = first_value.token();
 | ||
|         int a = dimension.dimension_value_int();
 | ||
|         auto maybe_b = dimension.dimension_unit().bytes_as_string_view().substring_view(1).to_number<int>();
 | ||
|         if (maybe_b.has_value()) {
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { a, maybe_b.value() };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
|     // <dashndashdigit-ident>
 | ||
|     if (is_dashndashdigit_ident(first_value)) {
 | ||
|         auto maybe_b = first_value.token().ident().bytes_as_string_view().substring_view(2).to_number<int>();
 | ||
|         if (maybe_b.has_value()) {
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { -1, maybe_b.value() };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
|     // -n
 | ||
|     // -n <signed-integer>
 | ||
|     // -n ['+' | '-'] <signless-integer>
 | ||
|     if (first_value.is_ident("-n"sv)) {
 | ||
|         values.skip_whitespace();
 | ||
| 
 | ||
|         // -n <signed-integer>
 | ||
|         if (is_signed_integer(values.peek_token())) {
 | ||
|             int b = values.next_token().token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { -1, b };
 | ||
|         }
 | ||
| 
 | ||
|         // -n ['+' | '-'] <signless-integer>
 | ||
|         {
 | ||
|             auto child_transaction = transaction.create_child();
 | ||
|             auto const& second_value = values.next_token();
 | ||
|             values.skip_whitespace();
 | ||
|             auto const& third_value = values.next_token();
 | ||
| 
 | ||
|             if (is_sign(second_value) && is_signless_integer(third_value)) {
 | ||
|                 int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
 | ||
|                 child_transaction.commit();
 | ||
|                 return Selector::SimpleSelector::ANPlusBPattern { -1, b };
 | ||
|             }
 | ||
|         }
 | ||
| 
 | ||
|         // -n
 | ||
|         transaction.commit();
 | ||
|         return Selector::SimpleSelector::ANPlusBPattern { -1, 0 };
 | ||
|     }
 | ||
|     // -n- <signless-integer>
 | ||
|     if (first_value.is_ident("-n-"sv)) {
 | ||
|         values.skip_whitespace();
 | ||
|         auto const& second_value = values.next_token();
 | ||
|         if (is_signless_integer(second_value)) {
 | ||
|             int b = -second_value.token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { -1, b };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
| 
 | ||
|     // All that's left now are these:
 | ||
|     // '+'?† n
 | ||
|     // '+'?† n <signed-integer>
 | ||
|     // '+'?† n ['+' | '-'] <signless-integer>
 | ||
|     // '+'?† n- <signless-integer>
 | ||
|     // '+'?† <ndashdigit-ident>
 | ||
|     // In all of these cases, the + is optional, and has no effect.
 | ||
|     // So, we just skip the +, and carry on.
 | ||
|     if (!first_value.is_delim('+')) {
 | ||
|         values.reconsume_current_input_token();
 | ||
|         // We do *not* skip whitespace here.
 | ||
|     }
 | ||
| 
 | ||
|     auto const& first_after_plus = values.next_token();
 | ||
|     // '+'?† n
 | ||
|     // '+'?† n <signed-integer>
 | ||
|     // '+'?† n ['+' | '-'] <signless-integer>
 | ||
|     if (first_after_plus.is_ident("n"sv)) {
 | ||
|         values.skip_whitespace();
 | ||
| 
 | ||
|         // '+'?† n <signed-integer>
 | ||
|         if (is_signed_integer(values.peek_token())) {
 | ||
|             int b = values.next_token().token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { 1, b };
 | ||
|         }
 | ||
| 
 | ||
|         // '+'?† n ['+' | '-'] <signless-integer>
 | ||
|         {
 | ||
|             auto child_transaction = transaction.create_child();
 | ||
|             auto const& second_value = values.next_token();
 | ||
|             values.skip_whitespace();
 | ||
|             auto const& third_value = values.next_token();
 | ||
| 
 | ||
|             if (is_sign(second_value) && is_signless_integer(third_value)) {
 | ||
|                 int b = third_value.token().to_integer() * (second_value.is_delim('+') ? 1 : -1);
 | ||
|                 child_transaction.commit();
 | ||
|                 return Selector::SimpleSelector::ANPlusBPattern { 1, b };
 | ||
|             }
 | ||
|         }
 | ||
| 
 | ||
|         // '+'?† n
 | ||
|         transaction.commit();
 | ||
|         return Selector::SimpleSelector::ANPlusBPattern { 1, 0 };
 | ||
|     }
 | ||
| 
 | ||
|     // '+'?† n- <signless-integer>
 | ||
|     if (first_after_plus.is_ident("n-"sv)) {
 | ||
|         values.skip_whitespace();
 | ||
|         auto const& second_value = values.next_token();
 | ||
|         if (is_signless_integer(second_value)) {
 | ||
|             int b = -second_value.token().to_integer();
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { 1, b };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
| 
 | ||
|     // '+'?† <ndashdigit-ident>
 | ||
|     if (is_ndashdigit_ident(first_after_plus)) {
 | ||
|         auto maybe_b = first_after_plus.token().ident().bytes_as_string_view().substring_view(1).to_number<int>();
 | ||
|         if (maybe_b.has_value()) {
 | ||
|             transaction.commit();
 | ||
|             return Selector::SimpleSelector::ANPlusBPattern { 1, maybe_b.value() };
 | ||
|         }
 | ||
| 
 | ||
|         return syntax_error();
 | ||
|     }
 | ||
| 
 | ||
|     return syntax_error();
 | ||
| }
 | ||
| 
 | ||
| }
 |