| /*============================================================================= | |
| Copyright (c) 1998-2003 Joel de Guzman | |
| http://spirit.sourceforge.net/ | |
| Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
| =============================================================================*/ | |
| #if !defined(BOOST_SPIRIT_PARSER_HPP) | |
| #define BOOST_SPIRIT_PARSER_HPP | |
| #include <boost/config.hpp> | |
| #include <boost/type_traits/remove_reference.hpp> | |
| #include <boost/spirit/home/classic/namespace.hpp> | |
| #include <boost/spirit/home/classic/core/scanner/scanner.hpp> | |
| #include <boost/spirit/home/classic/core/nil.hpp> | |
| namespace boost { namespace spirit { | |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN | |
| template <typename ParserT, typename ActionT> | |
| class action; // forward declaration | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // Parser categories | |
| // | |
| // Helper template classes to distinguish different types of | |
| // parsers. The following categories are the most generic. More | |
| // specific types may inherit from these. Each parser has a typedef | |
| // parser_category_t that defines its category. By default, if one | |
| // is not specified, it will inherit from the base parser class | |
| // which typedefs its parser_category_t as plain_parser_category. | |
| // | |
| // - plain parser has nothing special | |
| // - binary parser has subject a and b (e.g. alternative) | |
| // - unary parser has single subject (e.g. kleene star) | |
| // - action parser has an attached action parser | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| struct plain_parser_category {}; | |
| struct binary_parser_category : plain_parser_category {}; | |
| struct unary_parser_category : plain_parser_category {}; | |
| struct action_parser_category : unary_parser_category {}; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // parser_result metafunction | |
| // | |
| // Given a scanner type ScannerT and a parser type ParserT, the | |
| // parser_result metafunction provides the actual result of the | |
| // parser. | |
| // | |
| // Usage: | |
| // | |
| // typename parser_result<ParserT, ScannerT>::type | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| template <typename ParserT, typename ScannerT> | |
| struct parser_result | |
| { | |
| typedef typename boost::remove_reference<ParserT>::type parser_type; | |
| typedef typename parser_type::template result<ScannerT>::type type; | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // parser class | |
| // | |
| // This class is a protocol base class for all parsers. This is | |
| // essentially an interface contract. The parser class does not | |
| // really know how to parse anything but instead relies on the | |
| // template parameter DerivedT (which obviously is assumed to be a | |
| // subclass) to do the actual parsing. | |
| // | |
| // Concrete sub-classes inheriting from parser must have a | |
| // corresponding member function parse(...) compatible with the | |
| // conceptual Interface: | |
| // | |
| // template <typename ScannerT> | |
| // RT parse(ScannerT const& scan) const; | |
| // | |
| // where RT is the desired return type of the parser and ScannerT | |
| // scan is the scanner (see scanner.hpp). | |
| // | |
| // Concrete sub-classes inheriting from parser in most cases need to | |
| // have a nested meta-function result that returns the result type | |
| // of the parser's parse member function, given a scanner type. The | |
| // meta-function has the form: | |
| // | |
| // template <typename ScannerT> | |
| // struct result | |
| // { | |
| // typedef RT type; | |
| // }; | |
| // | |
| // where RT is the desired return type of the parser. This is | |
| // usually, but not always, dependent on the template parameter | |
| // ScannerT. If a parser does not supply a result metafunction, a | |
| // default is provided by the base parser class. | |
| // | |
| // The parser's derived() member function returns a reference to the | |
| // parser as its derived object. | |
| // | |
| // An operator[] is provided. The operator returns a semantic action | |
| // handler (see actions.hpp). | |
| // | |
| // Each parser has a typedef embed_t. This typedef specifies how a | |
| // parser is embedded in a composite (see composite.hpp). By | |
| // default, if one is not specified, the parser will be embedded by | |
| // value. That is, a copy of the parser is placed as a member | |
| // variable of the composite. Most parsers are embedded by value. In | |
| // certain situations however, this is not desirable or possible. | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| template <typename DerivedT> | |
| struct parser | |
| { | |
| typedef DerivedT embed_t; | |
| typedef DerivedT derived_t; | |
| typedef plain_parser_category parser_category_t; | |
| template <typename ScannerT> | |
| struct result | |
| { | |
| typedef typename match_result<ScannerT, nil_t>::type type; | |
| }; | |
| DerivedT& derived() | |
| { | |
| return *static_cast<DerivedT*>(this); | |
| } | |
| DerivedT const& derived() const | |
| { | |
| return *static_cast<DerivedT const*>(this); | |
| } | |
| template <typename ActionT> | |
| action<DerivedT, ActionT> | |
| operator[](ActionT const& actor) const | |
| { | |
| return action<DerivedT, ActionT>(derived(), actor); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // parse_info | |
| // | |
| // Results returned by the free parse functions: | |
| // | |
| // stop: points to the final parse position (i.e parsing | |
| // processed the input up to this point). | |
| // | |
| // hit: true if parsing is successful. This may be full: | |
| // the parser consumed all the input, or partial: | |
| // the parser consumed only a portion of the input. | |
| // | |
| // full: true when we have a full hit (i.e the parser | |
| // consumed all the input. | |
| // | |
| // length: The number of characters consumed by the parser. | |
| // This is valid only if we have a successful hit | |
| // (either partial or full). | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| template <typename IteratorT = char const*> | |
| struct parse_info | |
| { | |
| IteratorT stop; | |
| bool hit; | |
| bool full; | |
| std::size_t length; | |
| parse_info( | |
| IteratorT const& stop_ = IteratorT(), | |
| bool hit_ = false, | |
| bool full_ = false, | |
| std::size_t length_ = 0) | |
| : stop(stop_) | |
| , hit(hit_) | |
| , full(full_) | |
| , length(length_) {} | |
| template <typename ParseInfoT> | |
| parse_info(ParseInfoT const& pi) | |
| : stop(pi.stop) | |
| , hit(pi.hit) | |
| , full(pi.full) | |
| , length(pi.length) {} | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // Generic parse function | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| template <typename IteratorT, typename DerivedT> | |
| parse_info<IteratorT> | |
| parse( | |
| IteratorT const& first, | |
| IteratorT const& last, | |
| parser<DerivedT> const& p); | |
| /////////////////////////////////////////////////////////////////////////// | |
| // | |
| // Parse function for null terminated strings | |
| // | |
| /////////////////////////////////////////////////////////////////////////// | |
| template <typename CharT, typename DerivedT> | |
| parse_info<CharT const*> | |
| parse( | |
| CharT const* str, | |
| parser<DerivedT> const& p); | |
| BOOST_SPIRIT_CLASSIC_NAMESPACE_END | |
| }} // namespace BOOST_SPIRIT_CLASSIC_NS | |
| #endif | |
| #include <boost/spirit/home/classic/core/impl/parser.ipp> |