// Copyright (c) 2001-2011 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 { #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS using boost::spirit::eps; #endif 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