/*============================================================================= | |
Copyright (c) 1998-2003 Joel de Guzman | |
Copyright (c) 2001 Daniel Nuffer | |
Copyright (c) 2002 Hartmut Kaiser | |
http://spirit.sourceforge.net/ | |
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_DIFFERENCE_HPP) | |
#define BOOST_SPIRIT_DIFFERENCE_HPP | |
#include <boost/spirit/home/classic/namespace.hpp> | |
#include <boost/spirit/home/classic/core/parser.hpp> | |
#include <boost/spirit/home/classic/core/primitives/primitives.hpp> | |
#include <boost/spirit/home/classic/core/composite/composite.hpp> | |
#include <boost/spirit/home/classic/meta/as_parser.hpp> | |
namespace boost { namespace spirit { | |
BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN | |
/////////////////////////////////////////////////////////////////////////// | |
// | |
// difference: a - b; Matches a but not b | |
// | |
// Handles expressions of the form: | |
// | |
// a - b | |
// | |
// where a and b are parsers. The expression returns a composite | |
// parser that matches a but not b. One (not both) of the operands | |
// may be a literal char, wchar_t or a primitive string char const*, | |
// wchar_t const*. | |
// | |
/////////////////////////////////////////////////////////////////////////// | |
struct difference_parser_gen; | |
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400) | |
#pragma warning(push) | |
#pragma warning(disable:4512) //assignment operator could not be generated | |
#endif | |
template <typename A, typename B> | |
struct difference | |
: public binary<A, B, parser<difference<A, B> > > | |
{ | |
typedef difference<A, B> self_t; | |
typedef binary_parser_category parser_category_t; | |
typedef difference_parser_gen parser_generator_t; | |
typedef binary<A, B, parser<self_t> > base_t; | |
difference(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; | |
if (result_t hl = this->left().parse(scan)) | |
{ | |
std::swap(save, scan.first); | |
result_t hr = this->right().parse(scan); | |
if (!hr || (hr.length() < hl.length())) | |
{ | |
scan.first = save; | |
return hl; | |
} | |
} | |
return scan.no_match(); | |
} | |
}; | |
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400) | |
#pragma warning(pop) | |
#endif | |
struct difference_parser_gen | |
{ | |
template <typename A, typename B> | |
struct result | |
{ | |
typedef | |
difference< | |
typename as_parser<A>::type | |
, typename as_parser<B>::type | |
> | |
type; | |
}; | |
template <typename A, typename B> | |
static difference< | |
typename as_parser<A>::type | |
, typename as_parser<B>::type | |
> | |
generate(A const& a, B const& b) | |
{ | |
return difference<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> | |
difference<A, B> | |
operator-(parser<A> const& a, parser<B> const& b); | |
template <typename A> | |
difference<A, chlit<char> > | |
operator-(parser<A> const& a, char b); | |
template <typename B> | |
difference<chlit<char>, B> | |
operator-(char a, parser<B> const& b); | |
template <typename A> | |
difference<A, strlit<char const*> > | |
operator-(parser<A> const& a, char const* b); | |
template <typename B> | |
difference<strlit<char const*>, B> | |
operator-(char const* a, parser<B> const& b); | |
template <typename A> | |
difference<A, chlit<wchar_t> > | |
operator-(parser<A> const& a, wchar_t b); | |
template <typename B> | |
difference<chlit<wchar_t>, B> | |
operator-(wchar_t a, parser<B> const& b); | |
template <typename A> | |
difference<A, strlit<wchar_t const*> > | |
operator-(parser<A> const& a, wchar_t const* b); | |
template <typename B> | |
difference<strlit<wchar_t const*>, B> | |
operator-(wchar_t const* a, parser<B> const& b); | |
BOOST_SPIRIT_CLASSIC_NAMESPACE_END | |
}} // namespace BOOST_SPIRIT_CLASSIC_NS | |
#endif | |
#include <boost/spirit/home/classic/core/composite/impl/difference.ipp> |