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- /*=============================================================================
- 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_RULE_HPP)
- #define BOOST_SPIRIT_RULE_HPP
- #include <boost/static_assert.hpp>
- ///////////////////////////////////////////////////////////////////////////////
- //
- // Spirit predefined maximum number of simultaneously usable different
- // scanner types.
- //
- // This limit defines the maximum number of possible different scanner
- // types for which a specific rule<> may be used. If this isn't defined, a
- // rule<> may be used with one scanner type only (multiple scanner support
- // is disabled).
- //
- ///////////////////////////////////////////////////////////////////////////////
- #if !defined(BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT)
- # define BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT 1
- #endif
- // Ensure a meaningful maximum number of simultaneously usable scanner types
- BOOST_STATIC_ASSERT(BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 0);
- #include <boost/scoped_ptr.hpp>
- #include <boost/spirit/home/classic/namespace.hpp>
- #include <boost/spirit/home/classic/core/non_terminal/impl/rule.ipp>
- #if BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1
- # include <boost/preprocessor/enum_params.hpp>
- #endif
- ///////////////////////////////////////////////////////////////////////////////
- namespace boost { namespace spirit {
- BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
- #if BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1
- ///////////////////////////////////////////////////////////////////////////
- //
- // scanner_list (a fake scanner)
- //
- // Typically, rules are tied to a specific scanner type and
- // a particular rule cannot be used with anything else. Sometimes
- // there's a need for rules that can accept more than one scanner
- // type. The scanner_list<S0, ...SN> can be used as a template
- // parameter to the rule class to specify up to the number of
- // scanner types defined by the BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT
- // constant. Example:
- //
- // rule<scanner_list<ScannerT0, ScannerT1> > r;
- //
- // *** This feature is available only to compilers that support
- // partial template specialization. ***
- //
- ///////////////////////////////////////////////////////////////////////////
- template <
- BOOST_PP_ENUM_PARAMS(
- BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT,
- typename ScannerT
- )
- >
- struct scanner_list : scanner_base {};
- #endif
- ///////////////////////////////////////////////////////////////////////////
- //
- // rule class
- //
- // The rule is a polymorphic parser that acts as a named place-
- // holder capturing the behavior of an EBNF expression assigned to
- // it.
- //
- // The rule is a template class parameterized by:
- //
- // 1) scanner (scanner_t, see scanner.hpp),
- // 2) the rule's context (context_t, see parser_context.hpp)
- // 3) an arbitrary tag (tag_t, see parser_id.hpp) that allows
- // a rule to be tagged for identification.
- //
- // These template parameters may be specified in any order. The
- // scanner will default to scanner<> when it is not specified.
- // The context will default to parser_context when not specified.
- // The tag will default to parser_address_tag when not specified.
- //
- // The definition of the rule (its right hand side, RHS) held by
- // the rule through a scoped_ptr. When a rule is seen in the RHS
- // of an assignment or copy construction EBNF expression, the rule
- // is held by the LHS rule by reference.
- //
- ///////////////////////////////////////////////////////////////////////////
- template <
- typename T0 = nil_t
- , typename T1 = nil_t
- , typename T2 = nil_t
- >
- class rule
- : public impl::rule_base<
- rule<T0, T1, T2>
- , rule<T0, T1, T2> const&
- , T0, T1, T2>
- {
- public:
- typedef rule<T0, T1, T2> self_t;
- typedef impl::rule_base<
- self_t
- , self_t const&
- , T0, T1, T2>
- base_t;
- typedef typename base_t::scanner_t scanner_t;
- typedef typename base_t::attr_t attr_t;
- typedef impl::abstract_parser<scanner_t, attr_t> abstract_parser_t;
- rule() : ptr() {}
- ~rule() {}
- rule(rule const& r)
- : ptr(new impl::concrete_parser<rule, scanner_t, attr_t>(r)) {}
- template <typename ParserT>
- rule(ParserT const& p)
- : ptr(new impl::concrete_parser<ParserT, scanner_t, attr_t>(p)) {}
- template <typename ParserT>
- rule& operator=(ParserT const& p)
- {
- ptr.reset(new impl::concrete_parser<ParserT, scanner_t, attr_t>(p));
- return *this;
- }
- rule& operator=(rule const& r)
- {
- ptr.reset(new impl::concrete_parser<rule, scanner_t, attr_t>(r));
- return *this;
- }
- rule<T0, T1, T2>
- copy() const
- {
- return rule<T0, T1, T2>(ptr.get() ? ptr->clone() : 0);
- }
- private:
- friend class impl::rule_base_access;
- abstract_parser_t*
- get() const
- {
- return ptr.get();
- }
- rule(abstract_parser_t* ptr_)
- : ptr(ptr_) {}
- rule(abstract_parser_t const* ptr_)
- : ptr(ptr_) {}
- scoped_ptr<abstract_parser_t> ptr;
- };
- BOOST_SPIRIT_CLASSIC_NAMESPACE_END
- }} // namespace BOOST_SPIRIT_CLASSIC_NS
- #endif
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