/*============================================================================= | |
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_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM) | |
#define SPIRIT_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM | |
#if defined(_MSC_VER) | |
#pragma once | |
#endif | |
#include <boost/spirit/home/qi/domain.hpp> | |
#include <boost/spirit/home/qi/detail/assign_to.hpp> | |
#include <boost/spirit/home/support/unused.hpp> | |
#include <boost/spirit/home/qi/detail/attributes.hpp> | |
#include <boost/variant.hpp> | |
#include <boost/mpl/bool.hpp> | |
namespace boost { namespace spirit { namespace qi { namespace detail | |
{ | |
template <typename Iterator, typename Context, typename Skipper, | |
typename Attribute> | |
struct alternative_function | |
{ | |
alternative_function( | |
Iterator& first, Iterator const& last, Context& context, | |
Skipper const& skipper, Attribute& attr) | |
: first(first), last(last), context(context), skipper(skipper), | |
attr(attr) | |
{ | |
} | |
template <typename Component> | |
bool call(Component const& component, mpl::true_) const | |
{ | |
// if Attribute is not a variant, then pass it as-is | |
return component.parse(first, last, context, skipper, attr); | |
} | |
template <typename Component> | |
bool call(Component const& component, mpl::false_) const | |
{ | |
// if Attribute is a variant or optional, then create an | |
// attribute for the Component with its expected type. | |
typename traits::attribute_of<Component, Context, Iterator>::type val; | |
if (component.parse(first, last, context, skipper, val)) | |
{ | |
traits::assign_to(val, attr); | |
return true; | |
} | |
return false; | |
} | |
template <typename Component> | |
bool operator()(Component const& component) const | |
{ | |
// return true if the parser succeeds | |
return call(component, | |
mpl::and_< | |
spirit::traits::not_is_variant<Attribute, qi::domain>, | |
spirit::traits::not_is_optional<Attribute, qi::domain> | |
>()); | |
} | |
Iterator& first; | |
Iterator const& last; | |
Context& context; | |
Skipper const& skipper; | |
Attribute& attr; | |
private: | |
// silence MSVC warning C4512: assignment operator could not be generated | |
alternative_function& operator= (alternative_function const&); | |
}; | |
template <typename Iterator, typename Context, typename Skipper> | |
struct alternative_function<Iterator, Context, Skipper, unused_type const> | |
{ | |
alternative_function( | |
Iterator& first, Iterator const& last, Context& context, | |
Skipper const& skipper, unused_type) | |
: first(first), last(last), context(context), skipper(skipper) | |
{ | |
} | |
template <typename Component> | |
bool operator()(Component const& component) | |
{ | |
// return true if the parser succeeds | |
return component.parse(first, last, context, skipper, | |
unused); | |
} | |
Iterator& first; | |
Iterator const& last; | |
Context& context; | |
Skipper const& skipper; | |
private: | |
// silence MSVC warning C4512: assignment operator could not be generated | |
alternative_function& operator= (alternative_function const&); | |
}; | |
}}}} | |
#endif |