qi/numeric/real.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2011      Bryce Lelbach
0004
0005     Distributed under the Boost Software License, Version 1.0. (See accompanying
0006     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 ==============================================================================*/
0008 #if !defined(BOOST_SPIRIT_REAL_APRIL_18_2006_0850AM)
0009 #define BOOST_SPIRIT_REAL_APRIL_18_2006_0850AM
0010
0011 #if defined(_MSC_VER)
0012 #pragma once
0013 #endif
0014
0015 #include <boost/spirit/home/qi/skip_over.hpp>
0016 #include <boost/spirit/home/qi/detail/enable_lit.hpp>
0017 #include <boost/spirit/home/qi/meta_compiler.hpp>
0018 #include <boost/spirit/home/qi/parser.hpp>
0019 #include <boost/spirit/home/qi/numeric/real_policies.hpp>
0020 #include <boost/spirit/home/qi/numeric/numeric_utils.hpp>
0021 #include <boost/spirit/home/qi/numeric/detail/real_impl.hpp>
0022 #include <boost/spirit/home/support/common_terminals.hpp>
0023 #include <boost/type_traits/is_same.hpp>
0024
0025 namespace boost { namespace spirit
0026 {
0027     namespace qi
0028     {
0029         ///////////////////////////////////////////////////////////////////////
0030         // forward declaration only
0031         template <typename T>
0032         struct real_policies;
0033
0034         ///////////////////////////////////////////////////////////////////////
0035         // This is the class that the user can instantiate directly in
0036         // order to create a customized real parser
0037         template <typename T = double, typename Policies = real_policies<T> >
0038         struct real_parser
0039           : spirit::terminal<tag::stateful_tag<Policies, tag::double_, T> >
0040         {
0041             typedef tag::stateful_tag<Policies, tag::double_, T> tag_type;
0042
0043             real_parser() {}
0044             real_parser(Policies const& p)
0045               : spirit::terminal<tag_type>(p) {}
0046         };
0047     }
0048
0049     ///////////////////////////////////////////////////////////////////////////
0050     // Enablers
0051     ///////////////////////////////////////////////////////////////////////////
0052     template <> // enables float_
0053     struct use_terminal<qi::domain, tag::float_>
0054       : mpl::true_ {};
0055
0056     template <> // enables double_
0057     struct use_terminal<qi::domain, tag::double_>
0058       : mpl::true_ {};
0059
0060     template <> // enables long_double
0061     struct use_terminal<qi::domain, tag::long_double>
0062       : mpl::true_ {};
0063
0064     ///////////////////////////////////////////////////////////////////////////
0065     template <typename A0> // enables lit(n)
0066     struct use_terminal<qi::domain
0067         , terminal_ex<tag::lit, fusion::vector1<A0> >
0068         , typename enable_if<is_same<A0, float> >::type>
0069       : mpl::true_ {};
0070
0071     template <typename A0> // enables lit(n)
0072     struct use_terminal<qi::domain
0073         , terminal_ex<tag::lit, fusion::vector1<A0> >
0074         , typename enable_if<is_same<A0, double> >::type>
0075       : mpl::true_ {};
0076
0077     template <typename A0> // enables lit(n)
0078     struct use_terminal<qi::domain
0079         , terminal_ex<tag::lit, fusion::vector1<A0> >
0080         , typename enable_if<is_same<A0, long double> >::type>
0081       : mpl::true_ {};
0082
0083     ///////////////////////////////////////////////////////////////////////////
0084     template <typename A0> // enables float_(...)
0085     struct use_terminal<qi::domain
0086       , terminal_ex<tag::float_, fusion::vector1<A0> >
0087     > : mpl::true_ {};
0088
0089     template <typename A0> // enables double_(...)
0090     struct use_terminal<qi::domain
0091       , terminal_ex<tag::double_, fusion::vector1<A0> >
0092     > : mpl::true_ {};
0093
0094     template <typename A0> // enables long_double(...)
0095     struct use_terminal<qi::domain
0096       , terminal_ex<tag::long_double, fusion::vector1<A0> >
0097     > : mpl::true_ {};
0098
0099     template <> // enables *lazy* float_(...)
0100     struct use_lazy_terminal<qi::domain, tag::float_, 1>
0101       : mpl::true_ {};
0102
0103     template <> // enables *lazy* double_(...)
0104     struct use_lazy_terminal<qi::domain, tag::double_, 1>
0105       : mpl::true_ {};
0106
0107     template <> // enables *lazy* long_double_(...)
0108     struct use_lazy_terminal<qi::domain, tag::long_double, 1>
0109       : mpl::true_ {};
0110
0111     ///////////////////////////////////////////////////////////////////////////
0112     // enables custom real_parser
0113     template <typename T, typename Policies>
0114     struct use_terminal<qi::domain
0115         , tag::stateful_tag<Policies, tag::double_, T> >
0116       : mpl::true_ {};
0117
0118     // enables custom real_parser(...)
0119     template <typename T, typename Policies, typename A0>
0120     struct use_terminal<qi::domain
0121         , terminal_ex<tag::stateful_tag<Policies, tag::double_, T>
0122         , fusion::vector1<A0> > >
0123       : mpl::true_ {};
0124
0125     // enables *lazy* custom real_parser(...)
0126     template <typename T, typename Policies>
0127     struct use_lazy_terminal<
0128         qi::domain
0129       , tag::stateful_tag<Policies, tag::double_, T>
0130       , 1 // arity
0131     > : mpl::true_ {};
0132 }}
0133
0134 namespace boost { namespace spirit { namespace qi
0135 {
0136 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
0137     using spirit::float_;
0138     using spirit::double_;
0139     using spirit::long_double;
0140     using spirit::lit; // lit(1.0) is equivalent to 1.0
0141 #endif
0142
0143     using spirit::float_type;
0144     using spirit::double_type;
0145     using spirit::long_double_type;
0146     using spirit::lit_type;
0147
0148     ///////////////////////////////////////////////////////////////////////////
0149     // This is the actual real number parser
0150     ///////////////////////////////////////////////////////////////////////////
0151     template <typename T, typename RealPolicies = real_policies<T> >
0152     struct any_real_parser
0153       : primitive_parser<any_real_parser<T, RealPolicies> >
0154     {
0155         template <typename Context, typename Iterator>
0156         struct attribute
0157         {
0158             typedef T type;
0159         };
0160
0161         template <typename Iterator, typename Context, typename Skipper>
0162         bool parse(Iterator& first, Iterator const& last
0163           , Context& /*context*/, Skipper const& skipper
0164           , T& attr_) const
0165         {
0166             typedef detail::real_impl<T, RealPolicies> extract;
0167             qi::skip_over(first, last, skipper);
0168             return extract::parse(first, last, attr_, RealPolicies());
0169         }
0170
0171         template <typename Iterator, typename Context
0172           , typename Skipper, typename Attribute>
0173         bool parse(Iterator& first, Iterator const& last
0174           , Context& context, Skipper const& skipper
0175           , Attribute& attr_param) const
0176         {
0177             // this case is called when Attribute is not T
0178             T attr_;
0179             if (parse(first, last, context, skipper, attr_))
0180             {
0181                 traits::assign_to(attr_, attr_param);
0182                 return true;
0183             }
0184             return false;
0185         }
0186
0187         template <typename Context>
0188         info what(Context& /*context*/) const
0189         {
0190             return info("real");
0191         }
0192     };
0193
0194     template <typename T, typename RealPolicies = real_policies<T>
0195             , bool no_attribute = true>
0196     struct literal_real_parser
0197       : primitive_parser<literal_real_parser<T, RealPolicies, no_attribute> >
0198     {
0199         template <typename Value>
0200         literal_real_parser(Value const& n) : n_(n) {}
0201
0202         template <typename Context, typename Iterator>
0203         struct attribute
0204           : mpl::if_c<no_attribute, unused_type, T>
0205         {};
0206
0207         template <typename Iterator, typename Context
0208           , typename Skipper, typename Attribute>
0209         bool parse(Iterator& first, Iterator const& last
0210           , Context&, Skipper const& skipper
0211           , Attribute& attr_param) const
0212         {
0213             typedef detail::real_impl<T, RealPolicies> extract;
0214             qi::skip_over(first, last, skipper);
0215
0216             Iterator save = first;
0217             T attr_;
0218
0219             if (extract::parse(first, last, attr_, RealPolicies()) &&
0220                 (attr_ == n_))
0221             {
0222                 traits::assign_to(attr_, attr_param);
0223                 return true;
0224             }
0225
0226             first = save;
0227             return false;
0228         }
0229
0230         template <typename Context>
0231         info what(Context& /*context*/) const
0232         {
0233             return info("real");
0234         }
0235
0236         T n_;
0237     };
0238
0239     ///////////////////////////////////////////////////////////////////////////
0240     // Parser generators: make_xxx function (objects)
0241     ///////////////////////////////////////////////////////////////////////////
0242     template <typename T, typename Policies = real_policies<T> >
0243     struct make_real
0244     {
0245         typedef any_real_parser<T, Policies> result_type;
0246
0247         result_type operator()(unused_type, unused_type) const
0248         {
0249             return result_type();
0250         }
0251     };
0252
0253     template <typename T, typename Policies = real_policies<T> >
0254     struct make_direct_real
0255     {
0256         typedef literal_real_parser<T, Policies, false> result_type;
0257
0258         template <typename Terminal>
0259         result_type operator()(Terminal const& term, unused_type) const
0260         {
0261             return result_type(T(fusion::at_c<0>(term.args)));
0262         }
0263     };
0264
0265     template <typename T, typename Policies = real_policies<T> >
0266     struct make_literal_real
0267     {
0268         typedef literal_real_parser<T, Policies> result_type;
0269
0270         template <typename Terminal>
0271         result_type operator()(Terminal const& term, unused_type) const
0272         {
0273             return result_type(fusion::at_c<0>(term.args));
0274         }
0275     };
0276
0277     ///////////////////////////////////////////////////////////////////////////
0278     template <typename Modifiers, typename A0>
0279     struct make_primitive<
0280           terminal_ex<tag::lit, fusion::vector1<A0> >
0281         , Modifiers, typename enable_if<is_same<A0, float> >::type>
0282       : make_literal_real<float> {};
0283
0284     template <typename Modifiers, typename A0>
0285     struct make_primitive<
0286           terminal_ex<tag::lit, fusion::vector1<A0> >
0287         , Modifiers, typename enable_if<is_same<A0, double> >::type>
0288       : make_literal_real<double> {};
0289
0290     template <typename Modifiers, typename A0>
0291     struct make_primitive<
0292           terminal_ex<tag::lit, fusion::vector1<A0> >
0293         , Modifiers, typename enable_if<is_same<A0, long double> >::type>
0294       : make_literal_real<long double> {};
0295
0296     ///////////////////////////////////////////////////////////////////////////
0297     template <typename T, typename Policies, typename Modifiers>
0298     struct make_primitive<
0299         tag::stateful_tag<Policies, tag::double_, T>, Modifiers>
0300       : make_real<T, Policies> {};
0301
0302     template <typename T, typename Policies, typename A0, typename Modifiers>
0303     struct make_primitive<
0304         terminal_ex<tag::stateful_tag<Policies, tag::double_, T>
0305       , fusion::vector1<A0> >, Modifiers>
0306       : make_direct_real<T, Policies> {};
0307
0308     ///////////////////////////////////////////////////////////////////////////
0309     template <typename Modifiers>
0310     struct make_primitive<tag::float_, Modifiers>
0311       : make_real<float> {};
0312
0313     template <typename Modifiers, typename A0>
0314     struct make_primitive<
0315         terminal_ex<tag::float_
0316       , fusion::vector1<A0> >, Modifiers>
0317       : make_direct_real<float> {};
0318
0319     ///////////////////////////////////////////////////////////////////////////
0320     template <typename Modifiers>
0321     struct make_primitive<tag::double_, Modifiers>
0322       : make_real<double> {};
0323
0324     template <typename Modifiers, typename A0>
0325     struct make_primitive<
0326         terminal_ex<tag::double_
0327       , fusion::vector1<A0> >, Modifiers>
0328       : make_direct_real<double> {};
0329
0330     ///////////////////////////////////////////////////////////////////////////
0331     template <typename Modifiers>
0332     struct make_primitive<tag::long_double, Modifiers>
0333       : make_real<long double> {};
0334
0335     template <typename Modifiers, typename A0>
0336     struct make_primitive<
0337         terminal_ex<tag::long_double
0338       , fusion::vector1<A0> >, Modifiers>
0339       : make_direct_real<long double> {};
0340 }}}
0341
0342 #endif