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- /*=============================================================================
- Copyright (c) 2001-2011 Joel de Guzman
- 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_EPS_MARCH_23_2007_0454PM)
- #define BOOST_SPIRIT_EPS_MARCH_23_2007_0454PM
- #if defined(_MSC_VER)
- #pragma once
- #endif
- #include <boost/spirit/home/qi/domain.hpp>
- #include <boost/spirit/home/qi/skip_over.hpp>
- #include <boost/spirit/home/qi/meta_compiler.hpp>
- #include <boost/spirit/home/support/unused.hpp>
- #include <boost/spirit/home/support/info.hpp>
- #include <boost/spirit/home/support/common_terminals.hpp>
- #include <boost/fusion/include/at.hpp>
- #include <boost/type_traits/is_convertible.hpp>
- namespace boost { namespace spirit
- {
- ///////////////////////////////////////////////////////////////////////////
- // Enablers
- ///////////////////////////////////////////////////////////////////////////
- template <>
- struct use_terminal<qi::domain, tag::eps> // enables eps
- : mpl::true_ {};
- template <typename A0>
- struct use_terminal<qi::domain
- , terminal_ex<tag::eps, fusion::vector1<A0> > // enables eps(bool-condition)
- > : is_convertible<A0, bool> {};
- template <> // enables eps(f)
- struct use_lazy_terminal<
- qi::domain, tag::eps, 1 /*arity*/
- > : mpl::true_ {};
- }}
- namespace boost { namespace spirit { namespace qi
- {
- #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
- using spirit::eps;
- #endif
- using spirit::eps_type;
- struct eps_parser : primitive_parser<eps_parser>
- {
- template <typename Context, typename Iterator>
- struct attribute
- {
- typedef unused_type type;
- };
- template <typename Iterator, typename Context
- , typename Skipper, typename Attribute>
- bool parse(Iterator& first, Iterator const& last
- , Context& /*context*/, Skipper const& skipper
- , Attribute& /*attr*/) const
- {
- qi::skip_over(first, last, skipper);
- return true;
- }
- template <typename Context>
- info what(Context& /*context*/) const
- {
- return info("eps");
- }
- };
- struct semantic_predicate : primitive_parser<semantic_predicate>
- {
- template <typename Context, typename Iterator>
- struct attribute
- {
- typedef unused_type type;
- };
- semantic_predicate(bool predicate_)
- : predicate(predicate_) {}
- template <typename Iterator, typename Context
- , typename Skipper, typename Attribute>
- bool parse(Iterator& first, Iterator const& last
- , Context& /*context*/, Skipper const& skipper
- , Attribute& /*attr*/) const
- {
- qi::skip_over(first, last, skipper);
- return predicate;
- }
- template <typename Context>
- info what(Context& /*context*/) const
- {
- return info("semantic-predicate");
- }
- bool predicate;
- };
- ///////////////////////////////////////////////////////////////////////////
- // Parser generators: make_xxx function (objects)
- ///////////////////////////////////////////////////////////////////////////
- template <typename Modifiers>
- struct make_primitive<tag::eps, Modifiers>
- {
- typedef eps_parser result_type;
- result_type operator()(unused_type, unused_type) const
- {
- return result_type();
- }
- };
- template <typename Modifiers, typename A0>
- struct make_primitive<
- terminal_ex<tag::eps, fusion::vector1<A0> >
- , Modifiers>
- {
- typedef semantic_predicate result_type;
- template <typename Terminal>
- result_type operator()(Terminal const& term, unused_type) const
- {
- return result_type(fusion::at_c<0>(term.args) ? true : false);
- }
- };
- }}}
- #endif
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