390 lines
16 KiB
C++
390 lines
16 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 Hartmut Kaiser
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Copyright (c) 2001-2011 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef BOOST_SPIRIT_KARMA_DETAIL_PASS_CONTAINER_HPP
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#define BOOST_SPIRIT_KARMA_DETAIL_PASS_CONTAINER_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/spirit/home/karma/detail/attributes.hpp>
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#include <boost/spirit/home/support/container.hpp>
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#include <boost/spirit/home/support/handles_container.hpp>
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#include <boost/spirit/home/support/detail/hold_any.hpp>
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#include <boost/type_traits/is_base_of.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/and.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/preprocessor/cat.hpp>
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#include <boost/preprocessor/repetition/repeat.hpp>
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#include <boost/range/iterator_range_core.hpp>
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#include <boost/fusion/include/deduce_sequence.hpp>
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namespace boost { namespace spirit { namespace karma { namespace detail
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{
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// Helper meta-function allowing to evaluate weak substitutability and
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// negate the result if the predicate (Sequence) is not true
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template <typename Sequence, typename Attribute, typename ValueType>
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struct negate_weak_substitute_if_not
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: mpl::if_<
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Sequence
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, typename traits::is_weak_substitute<Attribute, ValueType>::type
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, typename mpl::not_<
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traits::is_weak_substitute<Attribute, ValueType>
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>::type>
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{};
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// pass_through_container: utility to check decide whether a provided
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// container attribute needs to be passed through to the current component
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// or of we need to split the container by passing along instances of its
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// value type
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// if the expected attribute of the current component is neither a Fusion
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// sequence nor a container, we will pass through the provided container
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// only if its value type is not compatible with the component
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence, typename Enable = void>
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struct pass_through_container_base
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: negate_weak_substitute_if_not<Sequence, ValueType, Attribute>
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{};
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// Specialization for fusion sequences, in this case we check whether all
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// the types in the sequence are convertible to the lhs attribute.
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//
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// We return false if the rhs attribute itself is a fusion sequence, which
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// is compatible with the LHS sequence (we want to pass through this
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// attribute without it being split apart).
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence = mpl::true_>
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struct not_compatible_element
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: mpl::and_<
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negate_weak_substitute_if_not<Sequence, Container, Attribute>
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, negate_weak_substitute_if_not<Sequence, ValueType, Attribute> >
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{};
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// If the value type of the container is not a Fusion sequence, we pass
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// through the container if each of the elements of the Attribute
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// sequence is compatible with either the container or its value type.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence
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, bool IsSequence = fusion::traits::is_sequence<ValueType>::value>
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struct pass_through_container_fusion_sequence
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{
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typedef typename mpl::find_if<
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Attribute, not_compatible_element<Container, ValueType, mpl::_1>
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>::type iter;
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typedef typename mpl::end<Attribute>::type end;
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typedef typename is_same<iter, end>::type type;
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};
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// If both, the Attribute and the value type of the provided container
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// are Fusion sequences, we pass the container only if the two
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// sequences are not compatible.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container_fusion_sequence<
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Container, ValueType, Attribute, Sequence, true>
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{
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typedef typename mpl::find_if<
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Attribute
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, not_compatible_element<Container, ValueType, mpl::_1, Sequence>
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>::type iter;
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typedef typename mpl::end<Attribute>::type end;
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typedef typename is_same<iter, end>::type type;
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};
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container_base<Container, ValueType, Attribute
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, Sequence
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, typename enable_if<fusion::traits::is_sequence<Attribute> >::type>
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: pass_through_container_fusion_sequence<
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Container, ValueType, Attribute, Sequence>
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{};
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// Specialization for containers
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//
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// If the value type of the attribute of the current component is not
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// a Fusion sequence, we have to pass through the provided container if
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// both are compatible.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence, typename AttributeValueType
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, bool IsSequence = fusion::traits::is_sequence<AttributeValueType>::value>
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struct pass_through_container_container
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: mpl::or_<
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traits::is_weak_substitute<Container, Attribute>
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, traits::is_weak_substitute<Container, AttributeValueType> >
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{};
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// If the value type of the exposed container attribute is a Fusion
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// sequence, we use the already existing logic for those.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence, typename AttributeValueType>
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struct pass_through_container_container<
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Container, ValueType, Attribute, Sequence, AttributeValueType, true>
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: pass_through_container_fusion_sequence<
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Container, ValueType, AttributeValueType, Sequence>
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{};
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container_base<Container, ValueType, Attribute
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, Sequence
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, typename enable_if<traits::is_container<Attribute> >::type>
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: detail::pass_through_container_container<
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Container, ValueType, Attribute, Sequence
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, typename traits::container_value<Attribute>::type>
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{};
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// Specialization for exposed optional attributes
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//
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// If the type embedded in the exposed optional is not a Fusion
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// sequence we pass through the container attribute if it is compatible
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// either to the optionals embedded type or to the containers value
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// type.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence
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, bool IsSequence = fusion::traits::is_sequence<Attribute>::value>
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struct pass_through_container_optional
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: mpl::or_<
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traits::is_weak_substitute<Container, Attribute>
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, traits::is_weak_substitute<ValueType, Attribute> >
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{};
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// If the embedded type of the exposed optional attribute is a Fusion
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// sequence, we use the already existing logic for those.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container_optional<
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Container, ValueType, Attribute, Sequence, true>
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: pass_through_container_fusion_sequence<
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Container, ValueType, Attribute, Sequence>
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{};
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///////////////////////////////////////////////////////////////////////////
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container
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: pass_through_container_base<Container, ValueType, Attribute, Sequence>
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{};
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// Handle optional attributes
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container<
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Container, ValueType, boost::optional<Attribute>, Sequence>
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: pass_through_container_optional<
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Container, ValueType, Attribute, Sequence>
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{};
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// If both, the containers value type and the exposed attribute type are
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// optionals we are allowed to pass through the container only if the
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// embedded types of those optionals are not compatible.
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container<
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Container, boost::optional<ValueType>, boost::optional<Attribute>
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, Sequence>
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: mpl::not_<traits::is_weak_substitute<ValueType, Attribute> >
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{};
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// Specialization for exposed variant attributes
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//
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// We pass through the container attribute if at least one of the embedded
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// types in the variant requires to pass through the attribute
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#if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
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template <typename Container, typename ValueType, typename Sequence
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, typename T>
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struct pass_through_container<Container, ValueType, boost::variant<T>
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, Sequence>
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: pass_through_container<Container, ValueType, T, Sequence>
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{};
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template <typename Container, typename ValueType, typename Sequence
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, typename T0, typename ...TN>
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struct pass_through_container<Container, ValueType
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, boost::variant<T0, TN...>, Sequence>
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: mpl::bool_<pass_through_container<
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Container, ValueType, T0, Sequence
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>::type::value || pass_through_container<
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Container, ValueType, boost::variant<TN...>, Sequence
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>::type::value>
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{};
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#else
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#define BOOST_SPIRIT_PASS_THROUGH_CONTAINER(z, N, _) \
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pass_through_container<Container, ValueType, \
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BOOST_PP_CAT(T, N), Sequence>::type::value || \
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/***/
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// make sure unused variant parameters do not affect the outcome
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template <typename Container, typename ValueType, typename Sequence>
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struct pass_through_container<Container, ValueType
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, boost::detail::variant::void_, Sequence>
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: mpl::false_
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{};
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template <typename Container, typename ValueType, typename Sequence
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, BOOST_VARIANT_ENUM_PARAMS(typename T)>
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struct pass_through_container<Container, ValueType
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, boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Sequence>
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: mpl::bool_<BOOST_PP_REPEAT(BOOST_VARIANT_LIMIT_TYPES
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, BOOST_SPIRIT_PASS_THROUGH_CONTAINER, _) false>
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{};
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#undef BOOST_SPIRIT_PASS_THROUGH_CONTAINER
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#endif
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}}}}
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///////////////////////////////////////////////////////////////////////////////
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namespace boost { namespace spirit { namespace traits
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{
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///////////////////////////////////////////////////////////////////////////
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// forwarding customization point for domain karma::domain
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template <typename Container, typename ValueType, typename Attribute
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, typename Sequence>
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struct pass_through_container<
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Container, ValueType, Attribute, Sequence, karma::domain>
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: karma::detail::pass_through_container<
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Container, ValueType, Attribute, Sequence>
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{};
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}}}
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namespace boost { namespace spirit { namespace karma { namespace detail
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{
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template <typename Iterator>
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struct pass_container_base
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{
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pass_container_base(Iterator begin, Iterator end)
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: iter(begin), end(end)
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{}
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mutable Iterator iter;
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mutable Iterator end;
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};
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template <typename Iterator>
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struct pass_container_base<Iterator&>
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{
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pass_container_base(Iterator& begin, Iterator& end)
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: iter(begin), end(end)
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{}
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Iterator& iter;
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Iterator& end;
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};
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///////////////////////////////////////////////////////////////////////////
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// This function handles the case where the attribute (Attr) given
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// to the sequence is an STL container. This is a wrapper around F.
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// The function F does the actual generating.
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template <typename F, typename Attr, typename Iterator, typename Sequence>
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struct pass_container : pass_container_base<Iterator>
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{
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typedef pass_container_base<Iterator> base_type;
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typedef typename F::context_type context_type;
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pass_container(F const& f, Iterator begin, Iterator end)
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: base_type(begin, end)
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, f(f)
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{}
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bool is_at_end() const
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{
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return traits::compare(this->iter, this->end);
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}
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void next()
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{
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traits::next(this->iter);
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}
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// this is for the case when the current element expects an attribute
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// which is taken from the next entry in the container
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template <typename Component>
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bool dispatch_container(Component const& component, mpl::false_) const
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{
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// get the next value to generate from container
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if (!is_at_end() && !f(component, traits::deref(this->iter)))
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{
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// needs to return false as long as everything is ok
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traits::next(this->iter);
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return false;
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}
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// either no elements available any more or generation failed
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return true;
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}
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// this is for the case when the current element is able to handle an
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// attribute which is a container itself, this element will push its
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// data directly into the attribute container
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template <typename Component>
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bool dispatch_container(Component const& component, mpl::true_) const
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{
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return f(component, make_iterator_range(this->iter, this->end));
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}
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///////////////////////////////////////////////////////////////////////
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// this is for the case when the current element doesn't expect an
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// attribute
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template <typename Component>
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bool dispatch_attribute(Component const& component, mpl::false_) const
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{
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return f(component, unused);
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}
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// the current element expects an attribute
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template <typename Component>
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bool dispatch_attribute(Component const& component, mpl::true_) const
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{
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typedef typename traits::container_value<Attr>::type value_type;
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typedef typename
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traits::attribute_of<Component, context_type>::type
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lhs_attribute;
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// this predicate detects, whether the value type of the container
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// attribute is a substitute for the attribute of the current
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// element
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typedef mpl::and_<
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traits::handles_container<Component, Attr, context_type>
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, traits::pass_through_container<
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Attr, value_type, lhs_attribute, Sequence, karma::domain>
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> predicate;
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return dispatch_container(component, predicate());
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}
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// Dispatches to dispatch_main depending on the attribute type
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// of the Component
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template <typename Component>
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bool operator()(Component const& component) const
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{
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// we need to dispatch depending on the type of the attribute
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// of the current element (component). If this is has no attribute
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// we shouldn't use an element of the container but unused_type
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// instead
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typedef traits::not_is_unused<
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typename traits::attribute_of<Component, context_type>::type
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> predicate;
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return dispatch_attribute(component, predicate());
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}
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F f;
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// silence MSVC warning C4512: assignment operator could not be generated
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BOOST_DELETED_FUNCTION(pass_container& operator= (pass_container const&))
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};
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}}}}
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#endif
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