boost/spirit/home/x3/operator/detail/sequence.hpp
/*=============================================================================
Copyright (c) 2001-2014 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_X3_SEQUENCE_DETAIL_JAN_06_2013_1015AM)
#define BOOST_SPIRIT_X3_SEQUENCE_DETAIL_JAN_06_2013_1015AM
#include <boost/spirit/home/x3/support/traits/attribute_of.hpp>
#include <boost/spirit/home/x3/support/traits/attribute_category.hpp>
#include <boost/spirit/home/x3/support/traits/has_attribute.hpp>
#include <boost/spirit/home/x3/support/traits/is_substitute.hpp>
#include <boost/spirit/home/x3/support/traits/container_traits.hpp>
#include <boost/spirit/home/x3/support/traits/tuple_traits.hpp>
#include <boost/spirit/home/x3/core/detail/parse_into_container.hpp>
#include <boost/fusion/include/begin.hpp>
#include <boost/fusion/include/end.hpp>
#include <boost/fusion/include/advance.hpp>
#include <boost/fusion/include/deref.hpp>
#include <boost/fusion/include/empty.hpp>
#include <boost/fusion/include/front.hpp>
#include <boost/fusion/include/iterator_range.hpp>
#include <boost/mpl/if.hpp>
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_same.hpp>
#include <iterator> // for std::make_move_iterator
namespace boost { namespace spirit { namespace x3
{
template <typename Left, typename Right>
struct sequence;
}}}
namespace boost { namespace spirit { namespace x3 { namespace detail
{
template <typename Parser, typename Context, typename Enable = void>
struct sequence_size
{
static int const value = traits::has_attribute<Parser, Context>::value;
};
template <typename Parser, typename Context>
struct sequence_size_subject
: sequence_size<typename Parser::subject_type, Context> {};
template <typename Parser, typename Context>
struct sequence_size<Parser, Context
, typename enable_if_c<(Parser::is_pass_through_unary)>::type>
: sequence_size_subject<Parser, Context> {};
template <typename L, typename R, typename Context>
struct sequence_size<sequence<L, R>, Context>
{
static int const value =
sequence_size<L, Context>::value +
sequence_size<R, Context>::value;
};
struct pass_sequence_attribute_unused
{
typedef unused_type type;
template <typename T>
static unused_type
call(T&)
{
return unused_type();
}
};
template <typename Attribute>
struct pass_sequence_attribute_size_one_view
{
typedef typename fusion::result_of::deref<
typename fusion::result_of::begin<Attribute>::type
>::type type;
static type call(Attribute& attribute)
{
return fusion::deref(fusion::begin(attribute));
}
};
template <typename Attribute>
struct pass_through_sequence_attribute
{
typedef Attribute& type;
template <typename Attribute_>
static Attribute_&
call(Attribute_& attribute)
{
return attribute;
}
};
template <typename Parser, typename Attribute, typename Enable = void>
struct pass_sequence_attribute :
mpl::if_<
traits::is_size_one_view<Attribute>
, pass_sequence_attribute_size_one_view<Attribute>
, pass_through_sequence_attribute<Attribute>>::type {};
template <typename L, typename R, typename Attribute>
struct pass_sequence_attribute<sequence<L, R>, Attribute>
: pass_through_sequence_attribute<Attribute> {};
template <typename Parser, typename Attribute>
struct pass_sequence_attribute_subject :
pass_sequence_attribute<typename Parser::subject_type, Attribute> {};
template <typename Parser, typename Attribute>
struct pass_sequence_attribute<Parser, Attribute
, typename enable_if_c<(Parser::is_pass_through_unary)>::type>
: pass_sequence_attribute_subject<Parser, Attribute> {};
template <typename L, typename R, typename Attribute, typename Context
, typename Enable = void>
struct partition_attribute
{
using attr_category = typename traits::attribute_category<Attribute>::type;
static_assert(is_same<traits::tuple_attribute, attr_category>::value,
"The parser expects tuple-like attribute type");
static int const l_size = sequence_size<L, Context>::value;
static int const r_size = sequence_size<R, Context>::value;
static int constexpr actual_size = fusion::result_of::size<Attribute>::value;
static int constexpr expected_size = l_size + r_size;
// If you got an error here, then you are trying to pass
// a fusion sequence with the wrong number of elements
// as that expected by the (sequence) parser.
static_assert(
actual_size >= expected_size
, "Size of the passed attribute is less than expected."
);
static_assert(
actual_size <= expected_size
, "Size of the passed attribute is bigger than expected."
);
typedef typename fusion::result_of::begin<Attribute>::type l_begin;
typedef typename fusion::result_of::advance_c<l_begin, l_size>::type l_end;
typedef typename fusion::result_of::end<Attribute>::type r_end;
typedef fusion::iterator_range<l_begin, l_end> l_part;
typedef fusion::iterator_range<l_end, r_end> r_part;
typedef pass_sequence_attribute<L, l_part> l_pass;
typedef pass_sequence_attribute<R, r_part> r_pass;
static l_part left(Attribute& s)
{
auto i = fusion::begin(s);
return l_part(i, fusion::advance_c<l_size>(i));
}
static r_part right(Attribute& s)
{
return r_part(
fusion::advance_c<l_size>(fusion::begin(s))
, fusion::end(s));
}
};
template <typename L, typename R, typename Attribute, typename Context>
struct partition_attribute<L, R, Attribute, Context,
typename enable_if_c<(!traits::has_attribute<L, Context>::value &&
traits::has_attribute<R, Context>::value)>::type>
{
typedef unused_type l_part;
typedef Attribute& r_part;
typedef pass_sequence_attribute_unused l_pass;
typedef pass_sequence_attribute<R, Attribute> r_pass;
static unused_type left(Attribute&)
{
return unused;
}
static Attribute& right(Attribute& s)
{
return s;
}
};
template <typename L, typename R, typename Attribute, typename Context>
struct partition_attribute<L, R, Attribute, Context,
typename enable_if_c<(traits::has_attribute<L, Context>::value &&
!traits::has_attribute<R, Context>::value)>::type>
{
typedef Attribute& l_part;
typedef unused_type r_part;
typedef pass_sequence_attribute<L, Attribute> l_pass;
typedef pass_sequence_attribute_unused r_pass;
static Attribute& left(Attribute& s)
{
return s;
}
static unused_type right(Attribute&)
{
return unused;
}
};
template <typename L, typename R, typename Attribute, typename Context>
struct partition_attribute<L, R, Attribute, Context,
typename enable_if_c<(!traits::has_attribute<L, Context>::value &&
!traits::has_attribute<R, Context>::value)>::type>
{
typedef unused_type l_part;
typedef unused_type r_part;
typedef pass_sequence_attribute_unused l_pass;
typedef pass_sequence_attribute_unused r_pass;
static unused_type left(Attribute&)
{
return unused;
}
static unused_type right(Attribute&)
{
return unused;
}
};
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute, typename AttributeCategory>
bool parse_sequence(
Parser const& parser, Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr
, AttributeCategory)
{
using Left = typename Parser::left_type;
using Right = typename Parser::right_type;
using partition = partition_attribute<Left, Right, Attribute, Context>;
using l_pass = typename partition::l_pass;
using r_pass = typename partition::r_pass;
typename partition::l_part l_part = partition::left(attr);
typename partition::r_part r_part = partition::right(attr);
typename l_pass::type l_attr = l_pass::call(l_part);
typename r_pass::type r_attr = r_pass::call(r_part);
Iterator save = first;
if (parser.left.parse(first, last, context, rcontext, l_attr)
&& parser.right.parse(first, last, context, rcontext, r_attr))
return true;
first = save;
return false;
}
template <typename Parser, typename Context>
constexpr bool pass_sequence_container_attribute
= sequence_size<Parser, Context>::value > 1;
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
typename enable_if_c<pass_sequence_container_attribute<Parser, Context>, bool>::type
parse_sequence_container(
Parser const& parser
, Iterator& first, Iterator const& last, Context const& context
, RContext& rcontext, Attribute& attr)
{
return parser.parse(first, last, context, rcontext, attr);
}
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
typename disable_if_c<pass_sequence_container_attribute<Parser, Context>, bool>::type
parse_sequence_container(
Parser const& parser
, Iterator& first, Iterator const& last, Context const& context
, RContext& rcontext, Attribute& attr)
{
return parse_into_container(parser, first, last, context, rcontext, attr);
}
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
bool parse_sequence(
Parser const& parser , Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr
, traits::container_attribute)
{
Iterator save = first;
if (parse_sequence_container(parser.left, first, last, context, rcontext, attr)
&& parse_sequence_container(parser.right, first, last, context, rcontext, attr))
return true;
first = save;
return false;
}
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
bool parse_sequence_assoc(
Parser const& parser , Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr, mpl::false_ /*should_split*/)
{
return parse_into_container(parser, first, last, context, rcontext, attr);
}
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
bool parse_sequence_assoc(
Parser const& parser , Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr, mpl::true_ /*should_split*/)
{
Iterator save = first;
if (parser.left.parse( first, last, context, rcontext, attr)
&& parser.right.parse(first, last, context, rcontext, attr))
return true;
first = save;
return false;
}
template <typename Parser, typename Iterator, typename Context
, typename RContext, typename Attribute>
bool parse_sequence(
Parser const& parser, Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr
, traits::associative_attribute)
{
// we can come here in 2 cases:
// - when sequence is key >> value and therefore must
// be parsed with tuple synthesized attribute and then
// that tuple is used to save into associative attribute provided here.
// Example: key >> value;
//
// - when either this->left or this->right provides full key-value
// pair (like in case 1) and another one provides nothing.
// Example: eps >> rule<class x; fusion::map<...> >
//
// first case must be parsed as whole, and second one should
// be parsed separately for left and right.
typedef typename traits::attribute_of<
decltype(parser.left), Context>::type l_attr_type;
typedef typename traits::attribute_of<
decltype(parser.right), Context>::type r_attr_type;
typedef typename
mpl::or_<
is_same<l_attr_type, unused_type>
, is_same<r_attr_type, unused_type> >
should_split;
return parse_sequence_assoc(parser, first, last, context, rcontext, attr
, should_split());
}
template <typename Left, typename Right, typename Context, typename RContext>
struct parse_into_container_impl<sequence<Left, Right>, Context, RContext>
{
typedef sequence<Left, Right> parser_type;
template <typename Iterator, typename Attribute>
static bool call(
parser_type const& parser
, Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr, mpl::false_)
{
// inform user what went wrong if we jumped here in attempt to
// parse incompatible sequence into fusion::map
static_assert(!is_same< typename traits::attribute_category<Attribute>::type,
traits::associative_attribute>::value,
"To parse directly into fusion::map sequence must produce tuple attribute "
"where type of first element is existing key in fusion::map and second element "
"is value to be stored under that key");
Attribute attr_{};
if (!parse_sequence(parser
, first, last, context, rcontext, attr_, traits::container_attribute()))
{
return false;
}
traits::append(attr, std::make_move_iterator(traits::begin(attr_)),
std::make_move_iterator(traits::end(attr_)));
return true;
}
template <typename Iterator, typename Attribute>
static bool call(
parser_type const& parser
, Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr, mpl::true_)
{
return parse_into_container_base_impl<parser_type>::call(
parser, first, last, context, rcontext, attr);
}
template <typename Iterator, typename Attribute>
static bool call(
parser_type const& parser
, Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr)
{
typedef typename
traits::attribute_of<parser_type, Context>::type
attribute_type;
typedef typename
traits::container_value<Attribute>::type
value_type;
return call(parser, first, last, context, rcontext, attr
, typename traits::is_substitute<attribute_type, value_type>::type());
}
};
}}}}
#endif
