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Diffstat (limited to 'src/plugins/css/CSSParser.hpp')
| -rw-r--r-- | src/plugins/css/CSSParser.hpp | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/src/plugins/css/CSSParser.hpp b/src/plugins/css/CSSParser.hpp new file mode 100644 index 0000000..eb51dfa --- /dev/null +++ b/src/plugins/css/CSSParser.hpp @@ -0,0 +1,140 @@ +/* + Ousía + Copyright (C) 2014 Benjamin Paaßen, Andreas Stöckel + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef _OUSIA_CSS_PARSER_HPP_ +#define _OUSIA_CSS_PARSER_HPP_ + +#include <vector> +#include <tuple> + +#include <core/BufferedCharReader.hpp> +#include <core/CodeTokenizer.hpp> +#include <core/CSS.hpp> +#include <core/parser/Parser.hpp> + +namespace ousia { +namespace parser { +namespace css { + +/** + * This is a context free, recursive parser for a subset of the CSS3 language + * as defined by W3C. We allow the following grammar: + * + * DOC := SELECT RULESET DOC | epsilon + * SELECTORS := SELECT , SELECTORS | SELECT + * SELECT := SELECT' OPERATOR SELECT | SELECT' + * SELECT' := TYPE | TYPE:PSEUDO | TYPE::GEN_PSEUDO | + * TYPE:PSEUDO(ARGUMENTS) | + * TYPE::GEN_PSEUDO(ARGUMENTS) | TYPE#ID | + * TYPE[ATTRIBUTE] | TYPE[ATTRIBUTE=VALUE] + * TYPE := string + * PSEUDO := string + * GEN_PSEUDO := string + * ARGUMENTS := string , ARGUMENTS + * ID := string + * ATTRIBUTE := string + * VALUE := string + * OPERATOR := epsilon | > + * RULESET := epsilon | { RULES } + * RULES := RULE RULES | epsilon + * RULE := KEY : VALUE ; + * KEY := string + * VALUE := type-specific parser + * + * + * @author Benjamin Paassen - bpaassen@techfak.uni-bielefeld.de + */ +class CSSParser : public Parser { +private: + /** + * Implements the DOC Nonterminal + */ + void parseDocument(Rooted<SelectorNode> root, CodeTokenizer &tokenizer, + ParserContext &ctx); + /** + * Implements the SELECTORS Nonterminal and adds all leaf nodes of the + * resulting SelectorTree to the input leafList so that a parsed RuleSet can + * be inserted there. + */ + void parseSelectors(Rooted<SelectorNode> root, CodeTokenizer &tokenizer, + std::vector<Rooted<SelectorNode>> &leafList, + ParserContext &ctx); + /** + * Implements the SELECT Nonterminal, which in effect parses a SelectorPath + * of the SelectorTree and returns the beginning node of the path as first + * element as well as the leaf of the path as second tuple element. + */ + std::tuple<Rooted<SelectorNode>, Rooted<SelectorNode>> parseSelector( + CodeTokenizer &tokenizer, ParserContext &ctx); + + /** + * Implements the SELECT' Nonterminal, which parses a single Selector with + * its PseudoSelector and returns it. + */ + Rooted<SelectorNode> parsePrimitiveSelector(CodeTokenizer &tokenizer, + ParserContext &ctx); + + // TODO: Add RuleSet parsing methods. + + /** + * A convenience function to wrap around the tokenizer peek() function that + * only returns true if an instance of the expected type occurs. + * + * @param expectedType the ID of the expected type according to the + * CodeTokenizer specification. + * @param tokenizer the tokenizer for the input. + * @param t an empty token that gets the parsed token content + * if it has the expected type. + * @param force a flag to be set if it would be fatal for the + * parsing process to get the wrong type. In that case + * an exception is thrown. + * @return true iff a token of the expected type was found. + */ + bool expect(int expectedType, CodeTokenizer &tokenizer, Token &t, + bool force, ParserContext &ctx); + +public: + /** + * This parses the given input as CSS content as specified by the grammar + * seen above. The return value is a Rooted reference to the root of the + * SelectorTree. + * TODO: The RuleSet at the respective node at the tree lists all CSS Style + * rules that apply. + * + * @param is is a reference to the input stream that should be parsed. + * @param ctx is a reference to the context that should be used while + * parsing the document. + * @return returns the root node of the resulting SelectorTree. For more + * information on the return conventions consult the Parser.hpp. + */ + Rooted<Node> parse(std::istream &is, ParserContext &ctx) override; + + /** + * As befits a class called CSSParser, this Parser parses CSS. + */ + std::set<std::string> mimetypes() + { + std::set<std::string> out{"text/css"}; + return out; + } +}; +} +} +} + +#endif |