// Copyright (c) 2001-2011 Hartmut Kaiser
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// Copyright (c) 2010 Bryce Lelbach
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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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#ifndef BOOST_SPIRIT_KARMA_DIRECTIVE_AS_HPP
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#define BOOST_SPIRIT_KARMA_DIRECTIVE_AS_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/spirit/home/karma/meta_compiler.hpp>
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#include <boost/spirit/home/karma/generator.hpp>
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#include <boost/spirit/home/karma/domain.hpp>
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#include <boost/spirit/home/karma/detail/output_iterator.hpp>
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#include <boost/spirit/home/karma/detail/as.hpp>
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#include <boost/spirit/home/support/unused.hpp>
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#include <boost/spirit/home/support/info.hpp>
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#include <boost/spirit/home/support/common_terminals.hpp>
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#include <boost/spirit/home/support/has_semantic_action.hpp>
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#include <boost/spirit/home/support/handles_container.hpp>
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#include <boost/spirit/home/support/assert_msg.hpp>
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#include <boost/spirit/home/support/container.hpp>
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#include <boost/spirit/home/karma/detail/attributes.hpp>
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namespace boost { namespace spirit { namespace karma
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{
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template <typename T>
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struct as
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: stateful_tag_type<T, tag::as>
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{
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BOOST_SPIRIT_ASSERT_MSG(
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(traits::is_container<T>::type::value),
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error_type_must_be_a_container,
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(T));
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};
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}}}
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namespace boost { namespace spirit
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{
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///////////////////////////////////////////////////////////////////////////
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// Enablers
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///////////////////////////////////////////////////////////////////////////
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// enables as_string[...]
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template <>
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struct use_directive<karma::domain, tag::as_string>
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: mpl::true_ {};
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// enables as_wstring[...]
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template <>
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struct use_directive<karma::domain, tag::as_wstring>
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: mpl::true_ {};
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// enables as<T>[...]
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template <typename T>
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struct use_directive<karma::domain, tag::stateful_tag<T, tag::as> >
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: mpl::true_
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{};
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}}
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namespace boost { namespace spirit { namespace karma
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{
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#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
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using spirit::as_string;
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using spirit::as_wstring;
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#endif
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using spirit::as_string_type;
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using spirit::as_wstring_type;
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///////////////////////////////////////////////////////////////////////////
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// as_directive allows to hook custom conversions to string into the
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// output generation process
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename T>
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struct as_directive
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: unary_generator<as_directive<Subject, T> >
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{
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typedef Subject subject_type;
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typedef typename subject_type::properties properties;
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as_directive(Subject const& subject)
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: subject(subject) {}
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template <typename Context, typename Iterator>
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struct attribute
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{
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typedef T type;
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};
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template <typename OutputIterator, typename Context, typename Delimiter
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, typename Attribute>
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bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
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, Attribute const& attr) const
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{
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if (!traits::valid_as<T>(attr))
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return false;
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return subject.generate(sink, ctx, d, traits::as<T>(attr)) &&
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karma::delimit_out(sink, d); // always do post-delimiting
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}
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template <typename Context>
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info what(Context& context) const
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{
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return info("as", subject.what(context));
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}
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Subject subject;
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};
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///////////////////////////////////////////////////////////////////////////
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// Generator generators: make_xxx function (objects)
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename Modifiers>
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struct make_directive<tag::as_string, Subject, Modifiers>
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{
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typedef as_directive<Subject, std::string> result_type;
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result_type operator()(unused_type, Subject const& subject
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, unused_type) const
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{
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return result_type(subject);
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}
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};
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template <typename Subject, typename Modifiers>
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struct make_directive<tag::as_wstring, Subject, Modifiers>
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{
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typedef as_directive<Subject, std::basic_string<wchar_t> > result_type;
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result_type operator()(unused_type, Subject const& subject
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, unused_type) const
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{
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return result_type(subject);
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}
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};
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template <typename T, typename Subject, typename Modifiers>
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struct make_directive<tag::stateful_tag<T, tag::as>, Subject, Modifiers>
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{
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typedef as_directive<Subject, T> result_type;
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result_type operator()(unused_type, Subject const& subject
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, unused_type) const
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{
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return result_type(subject);
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}
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};
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}}}
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namespace boost { namespace spirit { namespace traits
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{
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename T>
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struct has_semantic_action<karma::as_directive<Subject, T> >
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: unary_has_semantic_action<Subject> {};
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject, typename T, typename Attribute
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, typename Context, typename Iterator>
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struct handles_container<karma::as_directive<Subject, T>, Attribute
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, Context, Iterator>
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: mpl::false_ {}; // always dereference attribute if used in sequences
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}}}
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#endif
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