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