1/*=============================================================================
2 Copyright (c) 2001-2011 Hartmut Kaiser
3 http://spirit.sourceforge.net/
4
5 Distributed under the Boost Software License, Version 1.0. (See accompanying
6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7=============================================================================*/
8
9//[customize_karma_embedded_container_includes
10#include <boost/spirit/include/karma.hpp>
11#include <iostream>
12#include <vector>
13//]
14
15///////////////////////////////////////////////////////////////////////////////
16//[customize_karma_embedded_container_data
17namespace client
18{
19 struct embedded_container
20 {
21 // expose the iterator of the embedded vector as our iterator
22 typedef std::vector<int>::const_iterator iterator;
23
24 // expose the type of the held data elements as our type
25 typedef std::vector<int>::value_type type;
26
27 // this is the vector holding the actual elements we need to generate
28 // output from
29 std::vector<int> data;
30 };
31}
32//]
33
34//[customize_karma_embedded_container_traits
35// All specializations of attribute customization points have to be placed into
36// the namespace boost::spirit::traits.
37//
38// Note that all templates below are specialized using the 'const' type.
39// This is necessary as all attributes in Karma are 'const'.
40namespace boost { namespace spirit { namespace traits
41{
42 // The specialization of the template 'is_container<>' will tell the
43 // library to treat the type 'client::embedded_container' as a
44 // container holding the items to generate output from.
45 template <>
46 struct is_container<client::embedded_container const>
47 : mpl::true_
48 {};
49
50 // The specialization of the template 'container_iterator<>' will be
51 // invoked by the library to evaluate the iterator type to be used
52 // for iterating the data elements in the container. We simply return
53 // the type of the iterator exposed by the embedded 'std::vector<int>'.
54 template <>
55 struct container_iterator<client::embedded_container const>
56 {
57 typedef client::embedded_container::iterator type;
58 };
59
60 // The specialization of the templates 'begin_container<>' and
61 // 'end_container<>' below will be used by the library to get the iterators
62 // pointing to the begin and the end of the data to generate output from.
63 // These specializations simply return the 'begin' and 'end' iterators as
64 // exposed by the embedded 'std::vector<int>'.
65 //
66 // The passed argument refers to the attribute instance passed to the list
67 // generator.
68 template <>
69 struct begin_container<client::embedded_container const>
70 {
71 static client::embedded_container::iterator
72 call(client::embedded_container const& d)
73 {
74 return d.data.begin();
75 }
76 };
77
78 template <>
79 struct end_container<client::embedded_container const>
80 {
81 static client::embedded_container::iterator
82 call(client::embedded_container const& d)
83 {
84 return d.data.end();
85 }
86 };
87}}}
88//]
89
90///////////////////////////////////////////////////////////////////////////////
91namespace karma = boost::spirit::karma;
92
93int main()
94{
95 //[customize_karma_embedded_container
96 client::embedded_container d1; // create some test data
97 d1.data.push_back(x: 1);
98 d1.data.push_back(x: 2);
99 d1.data.push_back(x: 3);
100
101 // use the instance of an 'client::embedded_container' instead of a
102 // STL vector
103 std::cout << karma::format(expr: karma::int_ % ", ", attr: d1) << std::endl; // prints: '1, 2, 3'
104 //]
105 return 0;
106}
107
108

source code of boost/libs/spirit/example/karma/customize_embedded_container.cpp