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137 lines
4.0 KiB
137 lines
4.0 KiB
// 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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