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1 | // Copyright (c) 2001-2011 Joel de Guzman |
2 | // Copyright (c) 2001-2011 Hartmut Kaiser | |
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_GENERATOR_BINDER_APR_17_2009_0952PM) | |
8 | #define BOOST_SPIRIT_GENERATOR_BINDER_APR_17_2009_0952PM | |
9 | ||
10 | #if defined(_MSC_VER) | |
11 | #pragma once | |
12 | #endif | |
13 | ||
14 | #include <boost/fusion/include/at.hpp> | |
15 | #include <boost/mpl/bool.hpp> | |
16 | #include <boost/spirit/home/support/has_semantic_action.hpp> | |
17 | ||
18 | namespace boost { namespace spirit { namespace karma { namespace detail | |
19 | { | |
20 | // generator_binder for plain rules | |
21 | template <typename Generator, typename Auto> | |
22 | struct generator_binder | |
23 | { | |
24 | generator_binder(Generator const& g) | |
25 | : g(g) {} | |
26 | ||
27 | template <typename OutputIterator, typename Delimiter, typename Context> | |
28 | bool call(OutputIterator& sink, Context& context | |
29 | , Delimiter const& delim, mpl::true_) const | |
30 | { | |
31 | // If DeducedAuto is false (semantic actions is present), the | |
32 | // component's attribute is unused. | |
33 | return g.generate(sink, context, delim, unused); | |
34 | } | |
35 | ||
36 | template <typename OutputIterator, typename Delimiter, typename Context> | |
37 | bool call(OutputIterator& sink, Context& context | |
38 | , Delimiter const& delim, mpl::false_) const | |
39 | { | |
40 | // If DeducedAuto is true (no semantic action), we pass the rule's | |
41 | // attribute on to the component. | |
42 | return g.generate(sink, context, delim | |
43 | , fusion::at_c<0>(context.attributes)); | |
44 | } | |
45 | ||
46 | template <typename OutputIterator, typename Delimiter, typename Context> | |
47 | bool operator()(OutputIterator& sink, Context& context | |
48 | , Delimiter const& delim) const | |
49 | { | |
50 | // If Auto is false, we need to deduce whether to apply auto rule | |
51 | typedef typename traits::has_semantic_action<Generator>::type auto_rule; | |
52 | return call(sink, context, delim, auto_rule()); | |
53 | } | |
54 | ||
55 | Generator g; | |
56 | }; | |
57 | ||
58 | // generator_binder for auto rules | |
59 | template <typename Generator> | |
60 | struct generator_binder<Generator, mpl::true_> | |
61 | { | |
62 | generator_binder(Generator const& g) | |
63 | : g(g) {} | |
64 | ||
65 | template <typename OutputIterator, typename Delimiter, typename Context> | |
66 | bool operator()(OutputIterator& sink, Context& context | |
67 | , Delimiter const& delim) const | |
68 | { | |
69 | // If Auto is true, the component's attribute is unused. | |
70 | return g.generate(sink, context, delim | |
71 | , fusion::at_c<0>(context.attributes)); | |
72 | } | |
73 | ||
74 | Generator g; | |
75 | }; | |
76 | ||
77 | template <typename Auto, typename Generator> | |
78 | inline generator_binder<Generator, Auto> | |
79 | bind_generator(Generator const& g) | |
80 | { | |
81 | return generator_binder<Generator, Auto>(g); | |
82 | } | |
83 | ||
84 | }}}} | |
85 | ||
86 | #endif |