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/*=============================================================================
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(SPIRIT_DIFFERENCE_FEBRUARY_11_2007_1250PM)
#define SPIRIT_DIFFERENCE_FEBRUARY_11_2007_1250PM
#include <boost/spirit/home/x3/support/traits/attribute_of.hpp>
#include <boost/spirit/home/x3/support/traits/has_attribute.hpp>
#include <boost/spirit/home/x3/core/parser.hpp>
namespace boost { namespace spirit { namespace x3
{
template <typename Left, typename Right>
struct difference : binary_parser<Left, Right, difference<Left, Right>>
{
typedef binary_parser<Left, Right, difference<Left, Right>> base_type;
static bool const handles_container = Left::handles_container;
difference(Left const& left, Right const& right)
: base_type(left, right) {}
template <typename Iterator, typename Context
, typename RContext, typename Attribute>
bool parse(Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr) const
{
// Try Right first
Iterator start = first;
if (this->right.parse(first, last, context, rcontext, unused))
{
// Right succeeds, we fail.
first = start;
return false;
}
// Right fails, now try Left
return this->left.parse(first, last, context, rcontext, attr);
}
template <typename Left_, typename Right_>
difference<Left_, Right_>
make(Left_ const& left, Right_ const& right) const
{
return { left, right };
}
};
template <typename Left, typename Right>
inline difference<
typename extension::as_parser<Left>::value_type
, typename extension::as_parser<Right>::value_type>
operator-(Left const& left, Right const& right)
{
return { as_parser(left), as_parser(right) };
}
}}}
namespace boost { namespace spirit { namespace x3 { namespace traits
{
template <typename Left, typename Right, typename Context>
struct attribute_of<x3::difference<Left, Right>, Context>
: attribute_of<Left, Context> {};
template <typename Left, typename Right, typename Context>
struct has_attribute<x3::difference<Left, Right>, Context>
: has_attribute<Left, Context> {};
}}}}
#endif
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