1/*=============================================================================
2 Copyright (c) 1998-2003 Joel de Guzman
3 Copyright (c) 2001 Daniel Nuffer
4 Copyright (c) 2002 Hartmut Kaiser
5 http://spirit.sourceforge.net/
6
7 Distributed under the Boost Software License, Version 1.0. (See accompanying
8 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9=============================================================================*/
10#if !defined(BOOST_SPIRIT_EXCLUSIVE_OR_HPP)
11#define BOOST_SPIRIT_EXCLUSIVE_OR_HPP
12
13#include <boost/spirit/home/classic/namespace.hpp>
14#include <boost/spirit/home/classic/core/parser.hpp>
15#include <boost/spirit/home/classic/core/primitives/primitives.hpp>
16#include <boost/spirit/home/classic/core/composite/composite.hpp>
17#include <boost/spirit/home/classic/meta/as_parser.hpp>
18
19namespace boost { namespace spirit {
20
21BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
22
23 ///////////////////////////////////////////////////////////////////////////
24 //
25 // exclusive_or class
26 //
27 // Handles expressions of the form:
28 //
29 // a ^ b
30 //
31 // where a and b are parsers. The expression returns a composite
32 // parser that matches a or b but not both. One (not both) of the
33 // operands may be a literal char, wchar_t or a primitive string
34 // char const*, wchar_t const*.
35 //
36 ///////////////////////////////////////////////////////////////////////////
37 struct exclusive_or_parser_gen;
38
39 template <typename A, typename B>
40 struct exclusive_or
41 : public binary<A, B, parser<exclusive_or<A, B> > >
42 {
43 typedef exclusive_or<A, B> self_t;
44 typedef binary_parser_category parser_category_t;
45 typedef exclusive_or_parser_gen parser_generator_t;
46 typedef binary<A, B, parser<self_t> > base_t;
47
48 exclusive_or(A const& a, B const& b)
49 : base_t(a, b) {}
50
51 template <typename ScannerT>
52 typename parser_result<self_t, ScannerT>::type
53 parse(ScannerT const& scan) const
54 {
55 typedef typename parser_result<self_t, ScannerT>::type result_t;
56 typedef typename ScannerT::iterator_t iterator_t;
57
58 iterator_t save = scan.first;
59 result_t l = this->left().parse(scan);
60 std::swap(save, scan.first);
61 result_t r = this->right().parse(scan);
62
63 if (l ? !bool(r) : bool(r))
64 {
65 if (l)
66 scan.first = save;
67 return l ? l : r;
68 }
69
70 return scan.no_match();
71 }
72 };
73
74 struct exclusive_or_parser_gen
75 {
76 template <typename A, typename B>
77 struct result
78 {
79 typedef
80 exclusive_or<
81 typename as_parser<A>::type
82 , typename as_parser<B>::type
83 >
84 type;
85 };
86
87 template <typename A, typename B>
88 static exclusive_or<
89 typename as_parser<A>::type
90 , typename as_parser<B>::type
91 >
92 generate(A const& a, B const& b)
93 {
94 return exclusive_or<BOOST_DEDUCED_TYPENAME as_parser<A>::type,
95 BOOST_DEDUCED_TYPENAME as_parser<B>::type>
96 (as_parser<A>::convert(a), as_parser<B>::convert(b));
97 }
98 };
99
100 template <typename A, typename B>
101 exclusive_or<A, B>
102 operator^(parser<A> const& a, parser<B> const& b);
103
104 template <typename A>
105 exclusive_or<A, chlit<char> >
106 operator^(parser<A> const& a, char b);
107
108 template <typename B>
109 exclusive_or<chlit<char>, B>
110 operator^(char a, parser<B> const& b);
111
112 template <typename A>
113 exclusive_or<A, strlit<char const*> >
114 operator^(parser<A> const& a, char const* b);
115
116 template <typename B>
117 exclusive_or<strlit<char const*>, B>
118 operator^(char const* a, parser<B> const& b);
119
120 template <typename A>
121 exclusive_or<A, chlit<wchar_t> >
122 operator^(parser<A> const& a, wchar_t b);
123
124 template <typename B>
125 exclusive_or<chlit<wchar_t>, B>
126 operator^(wchar_t a, parser<B> const& b);
127
128 template <typename A>
129 exclusive_or<A, strlit<wchar_t const*> >
130 operator^(parser<A> const& a, wchar_t const* b);
131
132 template <typename B>
133 exclusive_or<strlit<wchar_t const*>, B>
134 operator^(wchar_t const* a, parser<B> const& b);
135
136BOOST_SPIRIT_CLASSIC_NAMESPACE_END
137
138}} // namespace BOOST_SPIRIT_CLASSIC_NS
139
140#endif
141
142#include <boost/spirit/home/classic/core/composite/impl/exclusive_or.ipp>
143

source code of boost/libs/spirit/include/boost/spirit/home/classic/core/composite/exclusive_or.hpp