1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
/*=============================================================================
Copyright (c) 2001-2011 Joel de Guzman
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_DIFFERENCE_FEBRUARY_11_2007_1250PM)
#define SPIRIT_DIFFERENCE_FEBRUARY_11_2007_1250PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/spirit/home/qi/domain.hpp>
#include <boost/spirit/home/qi/meta_compiler.hpp>
#include <boost/spirit/home/qi/parser.hpp>
#include <boost/spirit/home/qi/detail/attributes.hpp>
#include <boost/spirit/home/support/info.hpp>
#include <boost/spirit/home/support/has_semantic_action.hpp>
#include <boost/spirit/home/support/handles_container.hpp>
#include <boost/fusion/include/at.hpp>
namespace boost { namespace spirit
{
///////////////////////////////////////////////////////////////////////////
// Enablers
///////////////////////////////////////////////////////////////////////////
template <>
struct use_operator<qi::domain, proto::tag::minus> // enables -
: mpl::true_ {};
}}
namespace boost { namespace spirit { namespace qi
{
template <typename Left, typename Right>
struct difference : binary_parser<difference<Left, Right> >
{
typedef Left left_type;
typedef Right right_type;
template <typename Context, typename Iterator>
struct attribute
{
typedef typename
traits::attribute_of<left_type, Context, Iterator>::type
type;
};
difference(Left const& left, Right const& right)
: left(left), right(right) {}
template <typename Iterator, typename Context
, typename Skipper, typename Attribute>
bool parse(Iterator& first, Iterator const& last
, Context& context, Skipper const& skipper
, Attribute& attr) const
{
// Unlike classic Spirit, with this version of difference, the rule
// lit("policeman") - "police" will always fail to match.
// Spirit2 does not count the matching chars while parsing and
// there is no reliable and fast way to check if the LHS matches
// more than the RHS.
// Try RHS first
Iterator start = first;
if (right.parse(first, last, context, skipper, unused))
{
// RHS succeeds, we fail.
first = start;
return false;
}
// RHS fails, now try LHS
return left.parse(first, last, context, skipper, attr);
}
template <typename Context>
info what(Context& context) const
{
return info("difference",
std::make_pair(left.what(context), right.what(context)));
}
Left left;
Right right;
};
///////////////////////////////////////////////////////////////////////////
// Parser generators: make_xxx function (objects)
///////////////////////////////////////////////////////////////////////////
template <typename Elements, typename Modifiers>
struct make_composite<proto::tag::minus, Elements, Modifiers>
: make_binary_composite<Elements, difference>
{};
}}}
namespace boost { namespace spirit { namespace traits
{
///////////////////////////////////////////////////////////////////////////
template <typename Left, typename Right>
struct has_semantic_action<qi::difference<Left, Right> >
: binary_has_semantic_action<Left, Right> {};
///////////////////////////////////////////////////////////////////////////
template <typename Left, typename Right, typename Attribute
, typename Context, typename Iterator>
struct handles_container<qi::difference<Left, Right>, Attribute, Context
, Iterator>
: binary_handles_container<Left, Right, Attribute, Context, Iterator> {};
}}}
#endif
|
