/usr/include/boost/spirit/home/x3/operator
Edit: /usr/include/boost/spirit/home/x3/operator/optional.hpp (3014B)
/*=============================================================================
Copyright (c) 2001-2014 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(BOOST_SPIRIT_X3_OPTIONAL_MARCH_23_2007_1117PM)
#define BOOST_SPIRIT_X3_OPTIONAL_MARCH_23_2007_1117PM
#include
#include
#include
#include
#include
#include
namespace boost { namespace spirit { namespace x3
{
template
struct optional : proxy>
{
typedef proxy> base_type;
static bool const handles_container = true;
constexpr optional(Subject const& subject)
: base_type(subject) {}
using base_type::parse_subject;
// Attribute is a container
template
bool parse_subject(Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr
, traits::container_attribute) const
{
detail::parse_into_container(
this->subject, first, last, context, rcontext, attr);
return true;
}
// Attribute is an optional
template
bool parse_subject(Iterator& first, Iterator const& last
, Context const& context, RContext& rcontext, Attribute& attr
, traits::optional_attribute) const
{
typedef typename
x3::traits::optional_value::type
value_type;
// create a local value
value_type val{};
if (this->subject.parse(first, last, context, rcontext, val))
{
// assign the parsed value into our attribute
x3::traits::move_to(val, attr);
}
return true;
}
};
template
constexpr optional::value_type>
operator-(Subject const& subject)
{
return { as_parser(subject) };
}
}}}
namespace boost { namespace spirit { namespace x3 { namespace traits
{
template
struct attribute_of, Context>
: build_optional<
typename attribute_of::type> {};
}}}}
#endif