90 lines
3.0 KiB
C++
Executable File
90 lines
3.0 KiB
C++
Executable File
// Copyright (c) 2001-2008 Hartmut Kaiser
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//
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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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#if !defined(BOOST_SPIRIT_KARMA_LAZY_MARCH_27_2007_1231PM)
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#define BOOST_SPIRIT_KARMA_LAZY_MARCH_27_2007_1231PM
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#include <boost/spirit/home/karma/domain.hpp>
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#include <boost/spirit/home/karma/delimit.hpp>
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#include <boost/spirit/home/support/attribute_of.hpp>
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#include <boost/spirit/home/support/unused.hpp>
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#include <boost/fusion/include/at.hpp>
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#include <boost/utility/result_of.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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namespace boost { namespace spirit { namespace karma
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{
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struct lazy_generator
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{
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template <typename Component, typename Context, typename Unused>
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struct attribute
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{
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typedef typename
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result_of::subject<Component>::type
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subject_type;
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typedef typename
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remove_reference<
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typename boost::result_of<
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subject_type(unused_type, Context)
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>::type
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>::type
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expr_type;
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typedef typename
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result_of::as_component<karma::domain, expr_type>::type
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component_type;
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typedef typename
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traits::attribute_of<
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karma::domain, component_type, Context>::type
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type;
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};
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template <typename Component, typename OutputIterator,
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typename Context, typename Delimiter, typename Parameter>
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static bool
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generate(Component const& component, OutputIterator& sink,
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Context& ctx, Delimiter const& d, Parameter const& param)
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{
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typedef typename
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result_of::subject<Component>::type
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subject_type;
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typedef typename
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remove_reference<
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typename boost::result_of<
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subject_type(unused_type, Context)
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>::type
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>::type
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expr_type;
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typedef typename
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result_of::as_component<karma::domain, expr_type>::type
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component_type;
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component_type subject
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= spirit::as_component(
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karma::domain(),
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fusion::at_c<0>(component.elements)(unused, ctx));
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return component_type::director::
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generate(subject, sink, ctx, d, param);
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}
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template <typename Component, typename Context>
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static std::string what(Component const& component, Context const& ctx)
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{
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std::string result = "lazy[";
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// FIXME: need to get at the what of the embedded component
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result += "...";
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result += "]";
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return result;
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}
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};
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}}}
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#endif
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