| /*============================================================================= |
| Copyright (c) 2001-2010 Hartmut Kaiser |
| http://spirit.sourceforge.net/ |
| |
| 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) |
| =============================================================================*/ |
| #include <boost/config/warning_disable.hpp> |
| |
| //[customize_karma_counter_includes |
| #include <boost/spirit/include/karma.hpp> |
| #include <iostream> |
| #include <vector> |
| //] |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| //[customize_karma_counter_data |
| namespace client |
| { |
| struct counter |
| { |
| // expose the current value of the counter as our iterator |
| typedef int iterator; |
| |
| // expose 'int' as the type of each generated element |
| typedef int type; |
| |
| counter(int max_count) |
| : counter_(0), max_count_(max_count) |
| {} |
| |
| int counter_; |
| int max_count_; |
| }; |
| } |
| //] |
| |
| //[customize_karma_counter_traits |
| // All specializations of attribute customization points have to be placed into |
| // the namespace boost::spirit::traits. |
| // |
| // Note that all templates below are specialized using the 'const' type. |
| // This is necessary as all attributes in Karma are 'const'. |
| namespace boost { namespace spirit { namespace traits |
| { |
| // The specialization of the template 'is_container<>' will tell the |
| // library to treat the type 'client::counter' as a container providing |
| // the items to generate output from. |
| template <> |
| struct is_container<client::counter const> |
| : mpl::true_ |
| {}; |
| |
| // The specialization of the template 'container_iterator<>' will be |
| // invoked by the library to evaluate the iterator type to be used |
| // for iterating the data elements in the container. |
| template <> |
| struct container_iterator<client::counter const> |
| { |
| typedef client::counter::iterator type; |
| }; |
| |
| // The specialization of the templates 'begin_container<>' and |
| // 'end_container<>' below will be used by the library to get the iterators |
| // pointing to the begin and the end of the data to generate output from. |
| // These specializations respectively return the initial and maximum |
| // counter values. |
| // |
| // The passed argument refers to the attribute instance passed to the list |
| // generator. |
| template <> |
| struct begin_container<client::counter const> |
| { |
| static client::counter::iterator |
| call(client::counter const& c) |
| { |
| return c.counter_; |
| } |
| }; |
| |
| template <> |
| struct end_container<client::counter const> |
| { |
| static client::counter::iterator |
| call(client::counter const& c) |
| { |
| return c.max_count_; |
| } |
| }; |
| }}} |
| //] |
| |
| //[customize_karma_counter_iterator_traits |
| // All specializations of attribute customization points have to be placed into |
| // the namespace boost::spirit::traits. |
| namespace boost { namespace spirit { namespace traits |
| { |
| // The specialization of the template 'deref_iterator<>' will be used to |
| // dereference the iterator associated with our counter data structure. |
| // Since we expose the current value as the iterator we just return the |
| // current iterator as the return value. |
| template <> |
| struct deref_iterator<client::counter::iterator> |
| { |
| typedef client::counter::type type; |
| |
| static type call(client::counter::iterator const& it) |
| { |
| return it; |
| } |
| }; |
| }}} |
| //] |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace karma = boost::spirit::karma; |
| |
| int main() |
| { |
| //[customize_karma_counter |
| // use the instance of a 'client::counter' instead of a STL vector |
| client::counter count(4); |
| std::cout << karma::format(karma::int_ % ", ", count) << std::endl; // prints: '0, 1, 2, 3' |
| //] |
| return 0; |
| } |
| |