// Copyright (c) 2001-2011 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_EPS_APRIL_21_2007_0246PM)
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#define BOOST_SPIRIT_KARMA_EPS_APRIL_21_2007_0246PM
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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/support/common_terminals.hpp>
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#include <boost/spirit/home/support/info.hpp>
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#include <boost/spirit/home/karma/domain.hpp>
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#include <boost/spirit/home/karma/meta_compiler.hpp>
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#include <boost/spirit/home/karma/delimit_out.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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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 eps
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template <>
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struct use_terminal<karma::domain, tag::eps>
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: mpl::true_ {};
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// enables eps(bool-condition)
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template <typename A0>
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struct use_terminal<karma::domain
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, terminal_ex<tag::eps, fusion::vector1<A0> > >
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: is_convertible<A0, bool> {};
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// enables lazy eps(f)
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template <>
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struct use_lazy_terminal<karma::domain, tag::eps, 1>
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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 boost::spirit::eps;
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#endif
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using boost::spirit::eps_type;
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struct eps_generator : primitive_generator<eps_generator>
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{
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template <typename Context, typename Unused>
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struct attribute
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{
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typedef unused_type type;
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};
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template <
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typename OutputIterator, typename Context, typename Delimiter
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, typename Attribute>
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static bool generate(OutputIterator& sink, Context&, Delimiter const& d
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, Attribute const& /*attr*/)
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{
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return 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 const& /*context*/) const
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{
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return info("eps");
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}
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};
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struct semantic_predicate : primitive_generator<semantic_predicate>
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{
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template <typename Context, typename Unused>
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struct attribute
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{
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typedef unused_type type;
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};
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semantic_predicate(bool predicate)
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: predicate_(predicate)
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{}
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template <
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typename OutputIterator, typename Context, typename Delimiter
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, typename Attribute>
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bool generate(OutputIterator& sink, Context&, Delimiter const& d
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, Attribute const& /*attr*/) const
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{
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// only do post-delimiting when predicate is true
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return predicate_ && karma::delimit_out(sink, d);
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}
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template <typename Context>
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info what(Context const& /*context*/) const
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{
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return info("semantic-predicate");
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}
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bool predicate_;
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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 Modifiers>
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struct make_primitive<tag::eps, Modifiers>
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{
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typedef eps_generator result_type;
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result_type operator()(unused_type, unused_type) const
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{
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return result_type();
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}
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};
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template <typename Modifiers, typename A0>
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struct make_primitive<
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terminal_ex<tag::eps, fusion::vector1<A0> >
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, Modifiers>
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{
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typedef semantic_predicate result_type;
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template <typename Terminal>
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result_type operator()(Terminal const& term, unused_type) const
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{
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return result_type(fusion::at_c<0>(term.args));
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}
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};
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}}}
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#endif
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