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1 | /*============================================================================= |
2 | Copyright (c) 2001-2014 Joel de Guzman | |
3 | ||
4 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | ==============================================================================*/ | |
7 | #if !defined(BOOST_SPIRIT_X3_EPS_MARCH_23_2007_0454PM) | |
8 | #define BOOST_SPIRIT_X3_EPS_MARCH_23_2007_0454PM | |
9 | ||
10 | #include <boost/spirit/home/x3/core/skip_over.hpp> | |
11 | #include <boost/spirit/home/x3/core/parser.hpp> | |
12 | #include <boost/spirit/home/x3/support/unused.hpp> | |
13 | ||
14 | namespace boost { namespace spirit { namespace x3 | |
15 | { | |
16 | struct rule_context_tag; | |
17 | ||
18 | struct semantic_predicate : parser<semantic_predicate> | |
19 | { | |
20 | typedef unused_type attribute_type; | |
21 | static bool const has_attribute = false; | |
22 | ||
23 | semantic_predicate(bool predicate) | |
24 | : predicate(predicate) {} | |
25 | ||
26 | template <typename Iterator, typename Context, typename Attribute> | |
27 | bool parse(Iterator& first, Iterator const& last | |
28 | , Context const& context, unused_type, Attribute&) const | |
29 | { | |
30 | x3::skip_over(first, last, context); | |
31 | return predicate; | |
32 | } | |
33 | ||
34 | bool predicate; | |
35 | }; | |
36 | ||
37 | template <typename F> | |
38 | struct lazy_semantic_predicate : parser<lazy_semantic_predicate<F>> | |
39 | { | |
40 | typedef unused_type attribute_type; | |
41 | static bool const has_attribute = false; | |
42 | ||
43 | lazy_semantic_predicate(F f) | |
44 | : f(f) {} | |
45 | ||
46 | template <typename Iterator, typename Context, typename Attribute> | |
47 | bool parse(Iterator& first, Iterator const& last | |
48 | , Context const& context, unused_type, Attribute& attr) const | |
49 | { | |
50 | x3::skip_over(first, last, context); | |
51 | return f(x3::get<rule_context_tag>(context)); | |
52 | } | |
53 | ||
54 | F f; | |
55 | }; | |
56 | ||
57 | struct eps_parser : parser<eps_parser> | |
58 | { | |
59 | typedef unused_type attribute_type; | |
60 | static bool const has_attribute = false; | |
61 | ||
62 | template <typename Iterator, typename Context | |
63 | , typename RuleContext, typename Attribute> | |
64 | bool parse(Iterator& first, Iterator const& last | |
65 | , Context const& context, RuleContext&, Attribute&) const | |
66 | { | |
67 | x3::skip_over(first, last, context); | |
68 | return true; | |
69 | } | |
70 | ||
71 | inline semantic_predicate operator()(bool predicate) const | |
72 | { | |
73 | return { predicate }; | |
74 | } | |
75 | ||
76 | template <typename F> | |
77 | lazy_semantic_predicate<F> operator()(F f) const | |
78 | { | |
79 | return { f }; | |
80 | } | |
81 | }; | |
82 | ||
83 | auto const eps = eps_parser{}; | |
84 | }}} | |
85 | ||
86 | #endif |