Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2011 Joel de Guzman
Chris@16:     Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: =============================================================================*/
Chris@16: #if !defined(SPIRIT_PASS_CONTAINER_JANUARY_06_2009_0802PM)
Chris@16: #define SPIRIT_PASS_CONTAINER_JANUARY_06_2009_0802PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/qi/detail/attributes.hpp>
Chris@16: #include <boost/spirit/home/support/container.hpp>
Chris@16: #include <boost/spirit/home/support/handles_container.hpp>
Chris@16: #include <boost/type_traits/is_base_of.hpp>
Chris@16: #include <boost/type_traits/is_convertible.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/and.hpp>
Chris@16: #include <boost/mpl/or.hpp>
Chris@16: #include <boost/preprocessor/cat.hpp>
Chris@16: #include <boost/preprocessor/repetition/repeat.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace qi { namespace detail
Chris@16: {
Chris@16:     // Helper meta-function allowing to evaluate weak substitutability and
Chris@16:     // negate the result if the predicate (Sequence) is not true
Chris@16:     template <typename Sequence, typename Attribute, typename ValueType>
Chris@16:     struct negate_weak_substitute_if_not
Chris@16:       : mpl::if_<
Chris@16:             Sequence
Chris@16:           , typename traits::is_weak_substitute<Attribute, ValueType>::type
Chris@16:           , typename mpl::not_<
Chris@101:                 traits::is_weak_substitute<Attribute, ValueType>
Chris@16:             >::type>
Chris@16:     {};
Chris@16: 
Chris@101:     // pass_through_container: utility to check decide whether a provided
Chris@101:     // container attribute needs to be passed through to the current component
Chris@16:     // or of we need to split the container by passing along instances of its
Chris@16:     // value type
Chris@16: 
Chris@101:     // if the expected attribute of the current component is neither a Fusion
Chris@101:     // sequence nor a container, we will pass through the provided container
Chris@16:     // only if its value type is not compatible with the component
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence, typename Enable = void>
Chris@16:     struct pass_through_container_base
Chris@16:       : negate_weak_substitute_if_not<Sequence, Attribute, ValueType>
Chris@16:     {};
Chris@16: 
Chris@16:     // Specialization for fusion sequences, in this case we check whether all
Chris@16:     // the types in the sequence are convertible to the lhs attribute.
Chris@101:     //
Chris@16:     // We return false if the rhs attribute itself is a fusion sequence, which
Chris@101:     // is compatible with the LHS sequence (we want to pass through this
Chris@16:     // attribute without it being split apart).
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence = mpl::true_>
Chris@16:     struct not_compatible_element
Chris@16:       : mpl::and_<
Chris@16:             negate_weak_substitute_if_not<Sequence, Attribute, Container>
Chris@16:           , negate_weak_substitute_if_not<Sequence, Attribute, ValueType> >
Chris@16:     {};
Chris@16: 
Chris@16:     // If the value type of the container is not a Fusion sequence, we pass
Chris@101:     // through the container if each of the elements of the Attribute
Chris@16:     // sequence is compatible with either the container or its value type.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence
Chris@16:       , bool IsSequence = fusion::traits::is_sequence<ValueType>::value>
Chris@16:     struct pass_through_container_fusion_sequence
Chris@16:     {
Chris@16:         typedef typename mpl::find_if<
Chris@16:             Attribute, not_compatible_element<Container, ValueType, mpl::_1>
Chris@16:         >::type iter;
Chris@16:         typedef typename mpl::end<Attribute>::type end;
Chris@16: 
Chris@16:         typedef typename is_same<iter, end>::type type;
Chris@16:     };
Chris@16: 
Chris@16:     // If both, the Attribute and the value type of the provided container
Chris@101:     // are Fusion sequences, we pass the container only if the two
Chris@16:     // sequences are not compatible.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container_fusion_sequence<
Chris@16:             Container, ValueType, Attribute, Sequence, true>
Chris@16:     {
Chris@16:         typedef typename mpl::find_if<
Chris@16:             Attribute
Chris@16:           , not_compatible_element<Container, ValueType, mpl::_1, Sequence>
Chris@16:         >::type iter;
Chris@16:         typedef typename mpl::end<Attribute>::type end;
Chris@16: 
Chris@16:         typedef typename is_same<iter, end>::type type;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container_base<Container, ValueType, Attribute
Chris@16:           , Sequence
Chris@16:           , typename enable_if<fusion::traits::is_sequence<Attribute> >::type>
Chris@16:       : pass_through_container_fusion_sequence<
Chris@16:             Container, ValueType, Attribute, Sequence>
Chris@16:     {};
Chris@16: 
Chris@16:     // Specialization for containers
Chris@16:     //
Chris@16:     // If the value type of the attribute of the current component is not
Chris@101:     // a Fusion sequence, we have to pass through the provided container if
Chris@16:     // both are compatible.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence, typename AttributeValueType
Chris@16:       , bool IsSequence = fusion::traits::is_sequence<AttributeValueType>::value>
Chris@16:     struct pass_through_container_container
Chris@16:       : mpl::or_<
Chris@101:             traits::is_weak_substitute<Attribute, Container>
Chris@16:           , traits::is_weak_substitute<AttributeValueType, Container> >
Chris@16:     {};
Chris@16: 
Chris@16:     // If the value type of the exposed container attribute is a Fusion
Chris@16:     // sequence, we use the already existing logic for those.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence, typename AttributeValueType>
Chris@16:     struct pass_through_container_container<
Chris@16:             Container, ValueType, Attribute, Sequence, AttributeValueType, true>
Chris@16:       : pass_through_container_fusion_sequence<
Chris@16:             Container, ValueType, AttributeValueType, Sequence>
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container_base<
Chris@16:             Container, ValueType, Attribute, Sequence
Chris@16:           , typename enable_if<traits::is_container<Attribute> >::type>
Chris@16:       : detail::pass_through_container_container<
Chris@16:             Container, ValueType, Attribute, Sequence
Chris@16:           , typename traits::container_value<Attribute>::type>
Chris@16:     {};
Chris@16: 
Chris@16:     // Specialization for exposed optional attributes
Chris@16:     //
Chris@101:     // If the type embedded in the exposed optional is not a Fusion
Chris@16:     // sequence we pass through the container attribute if it is compatible
Chris@101:     // either to the optionals embedded type or to the containers value
Chris@16:     // type.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence
Chris@16:       , bool IsSequence = fusion::traits::is_sequence<Attribute>::value>
Chris@16:     struct pass_through_container_optional
Chris@16:       : mpl::or_<
Chris@101:             traits::is_weak_substitute<Attribute, Container>
Chris@16:           , traits::is_weak_substitute<Attribute, ValueType> >
Chris@16:     {};
Chris@16: 
Chris@16:     // If the embedded type of the exposed optional attribute is a Fusion
Chris@16:     // sequence, we use the already existing logic for those.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container_optional<
Chris@16:                 Container, ValueType, Attribute, Sequence, true>
Chris@16:       : pass_through_container_fusion_sequence<
Chris@16:             Container, ValueType, Attribute, Sequence>
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container
Chris@101:       : pass_through_container_base<Container, ValueType, Attribute, Sequence>
Chris@16:     {};
Chris@16: 
Chris@16:     // Handle optional attributes
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container<
Chris@16:                 Container, ValueType, boost::optional<Attribute>, Sequence>
Chris@16:       : pass_through_container_optional<
Chris@101:             Container, ValueType, Attribute, Sequence>
Chris@16:     {};
Chris@16: 
Chris@16:     // If both, the containers value type and the exposed attribute type are
Chris@101:     // optionals we are allowed to pass through the container only if the
Chris@16:     // embedded types of those optionals are not compatible.
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container<
Chris@16:             Container, boost::optional<ValueType>, boost::optional<Attribute>
Chris@16:           , Sequence>
Chris@101:       : mpl::not_<traits::is_weak_substitute<Attribute, ValueType> >
Chris@16:     {};
Chris@16: 
Chris@16:     // Specialization for exposed variant attributes
Chris@101:     //
Chris@101:     // We pass through the container attribute if at least one of the embedded
Chris@16:     // types in the variant requires to pass through the attribute
Chris@16: 
Chris@101: #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
Chris@101:     template <typename Container, typename ValueType, typename Sequence
Chris@101:       , typename T>
Chris@101:     struct pass_through_container<Container, ValueType, boost::variant<T>
Chris@101:           , Sequence>
Chris@101:       : pass_through_container<Container, ValueType, T, Sequence>
Chris@101:     {};
Chris@101: 
Chris@101:     template <typename Container, typename ValueType, typename Sequence
Chris@101:       , typename T0, typename ...TN>
Chris@101:     struct pass_through_container<Container, ValueType
Chris@101:           , boost::variant<T0, TN...>, Sequence>
Chris@101:       : mpl::bool_<pass_through_container<
Chris@101:             Container, ValueType, T0, Sequence
Chris@101:             >::type::value || pass_through_container<
Chris@101:                 Container, ValueType, boost::variant<TN...>, Sequence
Chris@101:             >::type::value>
Chris@101:     {};
Chris@101: #else
Chris@16: #define BOOST_SPIRIT_PASS_THROUGH_CONTAINER(z, N, _)                          \
Chris@16:     pass_through_container<Container, ValueType,                              \
Chris@16:         BOOST_PP_CAT(T, N), Sequence>::type::value ||                         \
Chris@16:     /***/
Chris@16: 
Chris@16:     // make sure unused variant parameters do not affect the outcome
Chris@16:     template <typename Container, typename ValueType, typename Sequence>
Chris@16:     struct pass_through_container<Container, ValueType
Chris@16:           , boost::detail::variant::void_, Sequence>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Container, typename ValueType, typename Sequence
Chris@16:       , BOOST_VARIANT_ENUM_PARAMS(typename T)>
Chris@16:     struct pass_through_container<Container, ValueType
Chris@16:           , boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Sequence>
Chris@16:       : mpl::bool_<BOOST_PP_REPEAT(BOOST_VARIANT_LIMIT_TYPES
Chris@16:           , BOOST_SPIRIT_PASS_THROUGH_CONTAINER, _) false>
Chris@16:     {};
Chris@16: 
Chris@16: #undef BOOST_SPIRIT_PASS_THROUGH_CONTAINER
Chris@101: #endif
Chris@16: }}}}
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace boost { namespace spirit { namespace traits
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // forwarding customization point for domain qi::domain
Chris@16:     template <typename Container, typename ValueType, typename Attribute
Chris@16:       , typename Sequence>
Chris@16:     struct pass_through_container<
Chris@16:             Container, ValueType, Attribute, Sequence, qi::domain>
Chris@16:       : qi::detail::pass_through_container<
Chris@16:             Container, ValueType, Attribute, Sequence>
Chris@16:     {};
Chris@16: }}}
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace qi { namespace detail
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // This function handles the case where the attribute (Attr) given
Chris@16:     // the sequence is an STL container. This is a wrapper around F.
Chris@16:     // The function F does the actual parsing.
Chris@16:     template <typename F, typename Attr, typename Sequence>
Chris@16:     struct pass_container
Chris@16:     {
Chris@16:         typedef typename F::context_type context_type;
Chris@16:         typedef typename F::iterator_type iterator_type;
Chris@16: 
Chris@16:         pass_container(F const& f_, Attr& attr_)
Chris@16:           : f(f_), attr(attr_) {}
Chris@16: 
Chris@16:         // this is for the case when the current element exposes an attribute
Chris@16:         // which is pushed back onto the container
Chris@16:         template <typename Component>
Chris@16:         bool dispatch_container(Component const& component, mpl::false_) const
Chris@16:         {
Chris@16:             // synthesized attribute needs to be default constructed
Chris@16:             typename traits::container_value<Attr>::type val =
Chris@16:                 typename traits::container_value<Attr>::type();
Chris@16: 
Chris@16:             iterator_type save = f.first;
Chris@16:             bool r = f(component, val);
Chris@16:             if (!r)
Chris@16:             {
Chris@16:                 // push the parsed value into our attribute
Chris@16:                 r = !traits::push_back(attr, val);
Chris@16:                 if (r)
Chris@16:                     f.first = save;
Chris@16:             }
Chris@16:             return r;
Chris@16:         }
Chris@16: 
Chris@101:         // this is for the case when the current element is able to handle an
Chris@101:         // attribute which is a container itself, this element will push its
Chris@16:         // data directly into the attribute container
Chris@16:         template <typename Component>
Chris@16:         bool dispatch_container(Component const& component, mpl::true_) const
Chris@16:         {
Chris@16:             return f(component, attr);
Chris@16:         }
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@101:         // this is for the case when the current element doesn't expect an
Chris@16:         // attribute
Chris@16:         template <typename Component>
Chris@16:         bool dispatch_attribute(Component const& component, mpl::false_) const
Chris@16:         {
Chris@16:             return f(component, unused);
Chris@16:         }
Chris@16: 
Chris@16:         // the current element expects an attribute
Chris@16:         template <typename Component>
Chris@16:         bool dispatch_attribute(Component const& component, mpl::true_) const
Chris@16:         {
Chris@16:             typedef typename traits::container_value<Attr>::type value_type;
Chris@16:             typedef typename traits::attribute_of<
Chris@16:                 Component, context_type, iterator_type>::type
Chris@16:             rhs_attribute;
Chris@16: 
Chris@101:             // this predicate detects, whether the attribute of the current
Chris@16:             // element is a substitute for the value type of the container
Chris@101:             // attribute
Chris@16:             typedef mpl::and_<
Chris@16:                 traits::handles_container<
Chris@101:                     Component, Attr, context_type, iterator_type>
Chris@16:               , traits::pass_through_container<
Chris@16:                     Attr, value_type, rhs_attribute, Sequence, qi::domain>
Chris@16:             > predicate;
Chris@16: 
Chris@16:             return dispatch_container(component, predicate());
Chris@16:         }
Chris@16: 
Chris@16:         // Dispatches to dispatch_main depending on the attribute type
Chris@16:         // of the Component
Chris@16:         template <typename Component>
Chris@16:         bool operator()(Component const& component) const
Chris@16:         {
Chris@16:             // we need to dispatch depending on the type of the attribute
Chris@16:             // of the current element (component). If this is has no attribute
Chris@16:             // we shouldn't pass an attribute at all.
Chris@16:             typedef typename traits::not_is_unused<
Chris@16:                 typename traits::attribute_of<
Chris@16:                     Component, context_type, iterator_type
Chris@16:                 >::type
Chris@16:             >::type predicate;
Chris@16: 
Chris@16:             // ensure the attribute is actually a container type
Chris@16:             traits::make_container(attr);
Chris@16: 
Chris@16:             return dispatch_attribute(component, predicate());
Chris@16:         }
Chris@16: 
Chris@16:         F f;
Chris@16:         Attr& attr;
Chris@16: 
Chris@16:     private:
Chris@16:         // silence MSVC warning C4512: assignment operator could not be generated
Chris@16:         pass_container& operator= (pass_container const&);
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@101:     // Utility function to make a pass_container for container components
Chris@16:     // (kleene, list, plus, repeat)
Chris@16:     template <typename F, typename Attr>
Chris@16:     inline pass_container<F, Attr, mpl::false_>
Chris@16:     make_pass_container(F const& f, Attr& attr)
Chris@16:     {
Chris@16:         return pass_container<F, Attr, mpl::false_>(f, attr);
Chris@16:     }
Chris@16: 
Chris@16:     // Utility function to make a pass_container for sequences
Chris@16:     template <typename F, typename Attr>
Chris@16:     inline pass_container<F, Attr, mpl::true_>
Chris@16:     make_sequence_pass_container(F const& f, Attr& attr)
Chris@16:     {
Chris@16:         return pass_container<F, Attr, mpl::true_>(f, attr);
Chris@16:     }
Chris@16: }}}}
Chris@16: 
Chris@16: #endif
Chris@16: