boost/spirit/core/composite/exclusive_or.hpp
/*=============================================================================
Copyright (c) 1998-2003 Joel de Guzman
Copyright (c) 2001 Daniel Nuffer
Copyright (c) 2002 Hartmut Kaiser
http://spirit.sourceforge.net/
Use, modification and distribution is subject to 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_EXCLUSIVE_OR_HPP)
#define BOOST_SPIRIT_EXCLUSIVE_OR_HPP
#include <boost/spirit/core/parser.hpp>
#include <boost/spirit/core/primitives/primitives.hpp>
#include <boost/spirit/core/composite/composite.hpp>
#include <boost/spirit/meta/as_parser.hpp>
namespace boost { namespace spirit {
///////////////////////////////////////////////////////////////////////////
//
// exclusive_or class
//
// Handles expressions of the form:
//
// a ^ b
//
// where a and b are parsers. The expression returns a composite
// parser that matches a or b but not both. One (not both) of the
// operands may be a literal char, wchar_t or a primitive string
// char const*, wchar_t const*.
//
///////////////////////////////////////////////////////////////////////////
struct exclusive_or_parser_gen;
template <typename A, typename B>
struct exclusive_or
: public binary<A, B, parser<exclusive_or<A, B> > >
{
typedef exclusive_or<A, B> self_t;
typedef binary_parser_category parser_category_t;
typedef exclusive_or_parser_gen parser_generator_t;
typedef binary<A, B, parser<self_t> > base_t;
exclusive_or(A const& a, B const& b)
: base_t(a, b) {}
template <typename ScannerT>
typename parser_result<self_t, ScannerT>::type
parse(ScannerT const& scan) const
{
typedef typename parser_result<self_t, ScannerT>::type result_t;
typedef typename ScannerT::iterator_t iterator_t;
iterator_t save = scan.first;
result_t l = this->left().parse(scan);
std::swap(save, scan.first);
result_t r = this->right().parse(scan);
if (l ? !bool(r) : bool(r))
{
if (l)
scan.first = save;
return l ? l : r;
}
return scan.no_match();
}
};
struct exclusive_or_parser_gen
{
template <typename A, typename B>
struct result
{
typedef
exclusive_or<
typename as_parser<A>::type
, typename as_parser<B>::type
>
type;
};
template <typename A, typename B>
static exclusive_or<
typename as_parser<A>::type
, typename as_parser<B>::type
>
generate(A const& a, B const& b)
{
return exclusive_or<BOOST_DEDUCED_TYPENAME as_parser<A>::type,
BOOST_DEDUCED_TYPENAME as_parser<B>::type>
(as_parser<A>::convert(a), as_parser<B>::convert(b));
}
};
template <typename A, typename B>
exclusive_or<A, B>
operator^(parser<A> const& a, parser<B> const& b);
template <typename A>
exclusive_or<A, chlit<char> >
operator^(parser<A> const& a, char b);
template <typename B>
exclusive_or<chlit<char>, B>
operator^(char a, parser<B> const& b);
template <typename A>
exclusive_or<A, strlit<char const*> >
operator^(parser<A> const& a, char const* b);
template <typename B>
exclusive_or<strlit<char const*>, B>
operator^(char const* a, parser<B> const& b);
template <typename A>
exclusive_or<A, chlit<wchar_t> >
operator^(parser<A> const& a, wchar_t b);
template <typename B>
exclusive_or<chlit<wchar_t>, B>
operator^(wchar_t a, parser<B> const& b);
template <typename A>
exclusive_or<A, strlit<wchar_t const*> >
operator^(parser<A> const& a, wchar_t const* b);
template <typename B>
exclusive_or<strlit<wchar_t const*>, B>
operator^(wchar_t const* a, parser<B> const& b);
}} // namespace boost::spirit
#endif
#include <boost/spirit/core/composite/impl/exclusive_or.ipp>
