| // Copyright (c) 2001-2010 Hartmut Kaiser |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #if !defined(BOOST_SPIRIT_KARMA_EPS_APRIL_21_2007_0246PM) |
| #define BOOST_SPIRIT_KARMA_EPS_APRIL_21_2007_0246PM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/support/common_terminals.hpp> |
| #include <boost/spirit/home/support/info.hpp> |
| #include <boost/spirit/home/karma/domain.hpp> |
| #include <boost/spirit/home/karma/meta_compiler.hpp> |
| #include <boost/spirit/home/karma/delimit_out.hpp> |
| #include <boost/spirit/home/support/unused.hpp> |
| #include <boost/fusion/include/at.hpp> |
| |
| namespace boost { namespace spirit |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // Enablers |
| /////////////////////////////////////////////////////////////////////////// |
| |
| // enables eps |
| template <> |
| struct use_terminal<karma::domain, tag::eps> |
| : mpl::true_ {}; |
| |
| // enables eps(bool-condition) |
| template <typename A0> |
| struct use_terminal<karma::domain |
| , terminal_ex<tag::eps, fusion::vector1<A0> > > |
| : is_convertible<A0, bool> {}; |
| |
| // enables lazy eps(f) |
| template <> |
| struct use_lazy_terminal<karma::domain, tag::eps, 1> |
| : mpl::true_ {}; |
| |
| }} |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| namespace boost { namespace spirit { namespace karma |
| { |
| using boost::spirit::eps; |
| using boost::spirit::eps_type; |
| |
| struct eps_generator : primitive_generator<eps_generator> |
| { |
| template <typename Context, typename Unused> |
| struct attribute |
| { |
| typedef unused_type type; |
| }; |
| |
| template < |
| typename OutputIterator, typename Context, typename Delimiter |
| , typename Attribute> |
| static bool generate(OutputIterator& sink, Context&, Delimiter const& d |
| , Attribute const& /*attr*/) |
| { |
| return karma::delimit_out(sink, d); // always do post-delimiting |
| } |
| |
| template <typename Context> |
| info what(Context const& /*context*/) const |
| { |
| return info("eps"); |
| } |
| }; |
| |
| struct semantic_predicate : primitive_generator<semantic_predicate> |
| { |
| template <typename Context, typename Unused> |
| struct attribute |
| { |
| typedef unused_type type; |
| }; |
| |
| semantic_predicate(bool predicate) |
| : predicate_(predicate) |
| {} |
| |
| template < |
| typename OutputIterator, typename Context, typename Delimiter |
| , typename Attribute> |
| bool generate(OutputIterator& sink, Context&, Delimiter const& d |
| , Attribute const& /*attr*/) const |
| { |
| // only do post-delimiting when predicate is true |
| return predicate_ && karma::delimit_out(sink, d); |
| } |
| |
| template <typename Context> |
| info what(Context const& /*context*/) const |
| { |
| return info("semantic-predicate"); |
| } |
| |
| bool predicate_; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Generator generators: make_xxx function (objects) |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Modifiers> |
| struct make_primitive<tag::eps, Modifiers> |
| { |
| typedef eps_generator result_type; |
| result_type operator()(unused_type, unused_type) const |
| { |
| return result_type(); |
| } |
| }; |
| |
| template <typename Modifiers, typename A0> |
| struct make_primitive< |
| terminal_ex<tag::eps, fusion::vector1<A0> > |
| , Modifiers> |
| { |
| typedef semantic_predicate result_type; |
| |
| template <typename Terminal> |
| result_type operator()(Terminal const& term, unused_type) const |
| { |
| return result_type(fusion::at_c<0>(term.args)); |
| } |
| }; |
| |
| }}} |
| |
| #endif |