128 lines
3.9 KiB
C++
128 lines
3.9 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 Hartmut Kaiser
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http://spirit.sourceforge.net/
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#include <boost/config/warning_disable.hpp>
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//[customize_karma_counter_includes
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#include <boost/spirit/include/karma.hpp>
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#include <iostream>
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#include <vector>
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//]
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///////////////////////////////////////////////////////////////////////////////
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//[customize_karma_counter_data
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namespace client
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{
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struct counter
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{
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// expose the current value of the counter as our iterator
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typedef int iterator;
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// expose 'int' as the type of each generated element
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typedef int type;
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counter(int max_count)
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: counter_(0), max_count_(max_count)
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{}
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int counter_;
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int max_count_;
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};
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}
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//]
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//[customize_karma_counter_traits
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// All specializations of attribute customization points have to be placed into
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// the namespace boost::spirit::traits.
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//
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// Note that all templates below are specialized using the 'const' type.
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// This is necessary as all attributes in Karma are 'const'.
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namespace boost { namespace spirit { namespace traits
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{
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// The specialization of the template 'is_container<>' will tell the
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// library to treat the type 'client::counter' as a container providing
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// the items to generate output from.
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template <>
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struct is_container<client::counter const>
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: mpl::true_
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{};
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// The specialization of the template 'container_iterator<>' will be
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// invoked by the library to evaluate the iterator type to be used
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// for iterating the data elements in the container.
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template <>
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struct container_iterator<client::counter const>
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{
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typedef client::counter::iterator type;
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};
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// The specialization of the templates 'begin_container<>' and
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// 'end_container<>' below will be used by the library to get the iterators
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// pointing to the begin and the end of the data to generate output from.
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// These specializations respectively return the initial and maximum
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// counter values.
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//
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// The passed argument refers to the attribute instance passed to the list
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// generator.
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template <>
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struct begin_container<client::counter const>
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{
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static client::counter::iterator
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call(client::counter const& c)
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{
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return c.counter_;
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}
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};
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template <>
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struct end_container<client::counter const>
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{
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static client::counter::iterator
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call(client::counter const& c)
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{
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return c.max_count_;
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}
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};
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}}}
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//]
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//[customize_karma_counter_iterator_traits
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// All specializations of attribute customization points have to be placed into
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// the namespace boost::spirit::traits.
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namespace boost { namespace spirit { namespace traits
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{
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// The specialization of the template 'deref_iterator<>' will be used to
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// dereference the iterator associated with our counter data structure.
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// Since we expose the current value as the iterator we just return the
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// current iterator as the return value.
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template <>
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struct deref_iterator<client::counter::iterator>
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{
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typedef client::counter::type type;
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static type call(client::counter::iterator const& it)
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{
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return it;
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}
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};
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}}}
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//]
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///////////////////////////////////////////////////////////////////////////////
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namespace karma = boost::spirit::karma;
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int main()
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{
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//[customize_karma_counter
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// use the instance of a 'client::counter' instead of a STL vector
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client::counter count(4);
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std::cout << karma::format(karma::int_ % ", ", count) << std::endl; // prints: '0, 1, 2, 3'
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//]
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return 0;
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}
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