Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: // 
Chris@16: //  Distributed under the Boost Software License, Version 1.0. (See accompanying 
Chris@16: //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #if !defined(BOOST_SPIRIT_KARMA_BOOL_POLICIES_SEP_28_2009_1203PM)
Chris@16: #define BOOST_SPIRIT_KARMA_BOOL_POLICIES_SEP_28_2009_1203PM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/support/char_class.hpp>
Chris@16: #include <boost/spirit/home/karma/generator.hpp>
Chris@16: #include <boost/spirit/home/karma/char.hpp>
Chris@16: #include <boost/spirit/home/karma/numeric/detail/numeric_utils.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace karma 
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     //  bool_policies, if you need special handling of your boolean output
Chris@16:     //  just overload this policy class and use it as a template
Chris@16:     //  parameter to the karma::bool_generator boolean generator
Chris@16:     //
Chris@16:     //      struct special_bool_policy : karma::bool_policies<>
Chris@16:     //      {
Chris@16:     //          //  we want to spell the names of false as eurt (true backwards)
Chris@16:     //          template <typename CharEncoding, typename Tag
Chris@16:     //            , typename OutputIterator>
Chris@16:     //          static bool generate_false(OutputIterator& sink, bool)
Chris@16:     //          {
Chris@16:     //              return string_inserter<CharEncoding, Tag>::call(sink, "eurt");
Chris@16:     //          }
Chris@16:     //      };
Chris@16:     //
Chris@16:     //      typedef karma::bool_generator<special_bool_policy> backwards_bool;
Chris@16:     //
Chris@16:     //      karma::generate(sink, backwards_bool(), false); // will output: eurt
Chris@16:     //
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename T = bool>
Chris@16:     struct bool_policies
Chris@16:     {
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         // Expose the data type the generator is targeted at
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         typedef T value_type;
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         //  By default the policy doesn't require any special iterator 
Chris@16:         //  functionality. The boolean generator exposes its properties
Chris@16:         //  from here, so this needs to be updated in case other properties
Chris@16:         //  need to be implemented.
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         typedef mpl::int_<generator_properties::no_properties> properties;
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         //  This is the main function used to generate the output for a 
Chris@16:         //  boolean. It is called by the boolean generator in order 
Chris@16:         //  to perform the conversion. In theory all of the work can be 
Chris@16:         //  implemented here, but it is the easiest to use existing 
Chris@16:         //  functionality provided by the type specified by the template 
Chris@16:         //  parameter `Inserter`. 
Chris@16:         //
Chris@16:         //      sink: the output iterator to use for generation
Chris@16:         //      n:    the floating point number to convert 
Chris@16:         //      p:    the instance of the policy type used to instantiate this 
Chris@16:         //            floating point generator.
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         template <typename Inserter, typename OutputIterator, typename Policies>
Chris@16:         static bool
Chris@16:         call (OutputIterator& sink, T n, Policies const& p)
Chris@16:         {
Chris@16:             return Inserter::call_n(sink, n, p);
Chris@16:         }
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         //  Print the textual representations of a true boolean value
Chris@16:         //
Chris@16:         //      sink       The output iterator to use for generation
Chris@16:         //      b          The boolean value to convert. 
Chris@16:         //
Chris@16:         //  The CharEncoding and Tag template parameters are either of the type 
Chris@16:         //  unused_type or describes the character class and conversion to be 
Chris@16:         //  applied to any output possibly influenced by either the lower[...] 
Chris@16:         //  or upper[...] directives.
Chris@16:         //
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         template <typename CharEncoding, typename Tag, typename OutputIterator>
Chris@16:         static bool generate_true(OutputIterator& sink, T)
Chris@16:         {
Chris@16:             return string_inserter<CharEncoding, Tag>::call(sink, "true");
Chris@16:         }
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         //  Print the textual representations of a false boolean value
Chris@16:         //
Chris@16:         //      sink       The output iterator to use for generation
Chris@16:         //      b          The boolean value to convert. 
Chris@16:         //
Chris@16:         //  The CharEncoding and Tag template parameters are either of the type 
Chris@16:         //  unused_type or describes the character class and conversion to be 
Chris@16:         //  applied to any output possibly influenced by either the lower[...] 
Chris@16:         //  or upper[...] directives.
Chris@16:         //
Chris@16:         ///////////////////////////////////////////////////////////////////////
Chris@16:         template <typename CharEncoding, typename Tag, typename OutputIterator>
Chris@16:         static bool generate_false(OutputIterator& sink, T)
Chris@16:         {
Chris@16:             return string_inserter<CharEncoding, Tag>::call(sink, "false");
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif