qi/numeric/bool.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Hartmut Kaiser
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 #ifndef BOOST_SPIRIT_QI_NUMERIC_BOOL_HPP
0009 #define BOOST_SPIRIT_QI_NUMERIC_BOOL_HPP
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/bool_policies.hpp>
0020 #include <boost/spirit/home/support/common_terminals.hpp>
0021 #include <boost/mpl/assert.hpp>
0022 #include <boost/detail/workaround.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 bool_policies;
0033
0034         ///////////////////////////////////////////////////////////////////////
0035         // This is the class that the user can instantiate directly in
0036         // order to create a customized bool parser
0037         template <typename T, typename BoolPolicies = bool_policies<T> >
0038         struct bool_parser
0039           : spirit::terminal<tag::stateful_tag<BoolPolicies, tag::bool_, T> >
0040         {
0041             typedef tag::stateful_tag<BoolPolicies, tag::bool_, T> tag_type;
0042
0043             bool_parser() {}
0044             bool_parser(BoolPolicies const& data)
0045               : spirit::terminal<tag_type>(data) {}
0046         };
0047     }
0048
0049     ///////////////////////////////////////////////////////////////////////////
0050     // Enablers
0051     ///////////////////////////////////////////////////////////////////////////
0052     template <> // enables bool_
0053     struct use_terminal<qi::domain, tag::bool_>
0054       : mpl::true_ {};
0055
0056     template <> // enables true_
0057     struct use_terminal<qi::domain, tag::true_>
0058       : mpl::true_ {};
0059
0060     template <> // enables false_
0061     struct use_terminal<qi::domain, tag::false_>
0062       : mpl::true_ {};
0063
0064     ///////////////////////////////////////////////////////////////////////////
0065     template <typename A0> // enables lit(...)
0066     struct use_terminal<qi::domain
0067         , terminal_ex<tag::lit, fusion::vector1<A0> >
0068         , typename enable_if<is_same<A0, bool> >::type>
0069       : mpl::true_ {};
0070
0071     ///////////////////////////////////////////////////////////////////////////
0072     template <typename A0> // enables bool_(...)
0073     struct use_terminal<qi::domain
0074       , terminal_ex<tag::bool_, fusion::vector1<A0> >
0075     > : mpl::true_ {};
0076
0077     template <> // enables *lazy* bool_(...)
0078     struct use_lazy_terminal<qi::domain, tag::bool_, 1>
0079       : mpl::true_ {};
0080
0081     ///////////////////////////////////////////////////////////////////////////
0082     // enables any custom bool_parser
0083     template <typename T, typename BoolPolicies>
0084     struct use_terminal<qi::domain
0085         , tag::stateful_tag<BoolPolicies, tag::bool_, T> >
0086       : mpl::true_ {};
0087
0088     // enables any custom bool_parser(...)
0089     template <typename T, typename BoolPolicies, typename A0>
0090     struct use_terminal<qi::domain
0091         , terminal_ex<tag::stateful_tag<BoolPolicies, tag::bool_, T>
0092         , fusion::vector1<A0> > >
0093       : mpl::true_ {};
0094
0095     // enables *lazy* custom bool_parser(...)
0096     template <typename T, typename BoolPolicies>
0097     struct use_lazy_terminal<
0098         qi::domain
0099       , tag::stateful_tag<BoolPolicies, tag::bool_, T>
0100       , 1 // arity
0101     > : mpl::true_ {};
0102 }}
0103
0104 namespace boost { namespace spirit { namespace qi
0105 {
0106 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
0107     using spirit::bool_;
0108     using spirit::true_;
0109     using spirit::false_;
0110     using spirit::lit;    // lit(true) is equivalent to true
0111 #endif
0112     using spirit::bool_type;
0113     using spirit::true_type;
0114     using spirit::false_type;
0115     using spirit::lit_type;
0116
0117     namespace detail
0118     {
0119         template <typename T, typename BoolPolicies>
0120         struct bool_impl
0121         {
0122             template <typename Iterator, typename Attribute>
0123             static bool parse(Iterator& first, Iterator const& last
0124               , Attribute& attr, BoolPolicies const& p, bool allow_true = true
0125               , bool disallow_false = false)
0126             {
0127                 if (first == last)
0128                     return false;
0129
0130 #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600))
0131                 (void)p; // suppresses warning: C4100: 'p' : unreferenced formal parameter
0132 #endif
0133                 return (allow_true && p.parse_true(first, last, attr)) ||
0134                        (!disallow_false && p.parse_false(first, last, attr));
0135             }
0136         };
0137     }
0138
0139     ///////////////////////////////////////////////////////////////////////////
0140     // This actual boolean parser
0141     ///////////////////////////////////////////////////////////////////////////
0142     template <typename T, typename BoolPolicies = bool_policies<T> >
0143     struct any_bool_parser
0144       : primitive_parser<any_bool_parser<T, BoolPolicies> >
0145     {
0146         template <typename Context, typename Iterator>
0147         struct attribute
0148         {
0149             typedef T type;
0150         };
0151
0152         template <typename Iterator, typename Context
0153           , typename Skipper, typename Attribute>
0154         bool parse(Iterator& first, Iterator const& last
0155           , Context& /*context*/, Skipper const& skipper
0156           , Attribute& attr_) const
0157         {
0158             typedef detail::bool_impl<T, BoolPolicies> extract;
0159             qi::skip_over(first, last, skipper);
0160             return extract::parse(first, last, attr_, BoolPolicies());
0161         }
0162
0163         template <typename Context>
0164         info what(Context& /*context*/) const
0165         {
0166             return info("boolean");
0167         }
0168     };
0169
0170     template <typename T, typename BoolPolicies = bool_policies<T>
0171             , bool no_attribute = true>
0172     struct literal_bool_parser
0173       : primitive_parser<literal_bool_parser<T, BoolPolicies, no_attribute> >
0174     {
0175         template <typename Value>
0176         literal_bool_parser(Value const& n) : n_(n) {}
0177
0178         template <typename Context, typename Iterator>
0179         struct attribute
0180           : mpl::if_c<no_attribute, unused_type, T>
0181         {};
0182
0183         template <typename Iterator, typename Context
0184           , typename Skipper, typename Attribute>
0185         bool parse(Iterator& first, Iterator const& last
0186           , Context& /*context*/, Skipper const& skipper
0187           , Attribute& attr_) const
0188         {
0189             typedef detail::bool_impl<T, BoolPolicies> extract;
0190             qi::skip_over(first, last, skipper);
0191             return extract::parse(first, last, attr_, BoolPolicies(), n_, n_);
0192         }
0193
0194         template <typename Context>
0195         info what(Context& /*context*/) const
0196         {
0197             return info("boolean");
0198         }
0199
0200         T n_;
0201     };
0202
0203     ///////////////////////////////////////////////////////////////////////////
0204     // Parser generators: make_xxx function (objects)
0205     ///////////////////////////////////////////////////////////////////////////
0206     template <typename T, typename Modifiers
0207             , typename Policies = bool_policies<T> >
0208     struct make_bool
0209     {
0210         typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
0211             no_case;
0212
0213         typedef typename mpl::if_<
0214             mpl::and_<
0215                 no_case
0216               , is_same<bool_policies<T>, Policies>
0217             >
0218           , any_bool_parser<T, no_case_bool_policies<T> >
0219           , any_bool_parser<T, Policies> >::type
0220         result_type;
0221
0222         result_type operator()(unused_type, unused_type) const
0223         {
0224             return result_type();
0225         }
0226     };
0227
0228     template <typename T, typename Modifiers
0229             , typename Policies = bool_policies<T> >
0230     struct make_direct_bool
0231     {
0232         typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
0233             no_case;
0234
0235         typedef typename mpl::if_<
0236             mpl::and_<
0237                 no_case
0238               , is_same<bool_policies<T>, Policies>
0239             >
0240           , literal_bool_parser<T, no_case_bool_policies<T>, false>
0241           , literal_bool_parser<T, Policies, false> >::type
0242         result_type;
0243
0244         template <typename Terminal>
0245         result_type operator()(Terminal const& term, unused_type) const
0246         {
0247             return result_type(fusion::at_c<0>(term.args));
0248         }
0249     };
0250
0251     template <typename T, typename Modifiers, bool b
0252             , typename Policies = bool_policies<T> >
0253     struct make_predefined_direct_bool
0254     {
0255         typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
0256             no_case;
0257
0258         typedef typename mpl::if_<
0259             mpl::and_<
0260                 no_case
0261               , is_same<bool_policies<T>, Policies>
0262             >
0263           , literal_bool_parser<T, no_case_bool_policies<T>, false>
0264           , literal_bool_parser<T, Policies, false> >::type
0265         result_type;
0266
0267         result_type operator()(unused_type, unused_type) const
0268         {
0269             return result_type(b);
0270         }
0271     };
0272
0273     template <typename T, typename Modifiers
0274             , typename Policies = bool_policies<T> >
0275     struct make_literal_bool
0276     {
0277         typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
0278             no_case;
0279
0280         typedef typename mpl::if_<
0281             mpl::and_<
0282                 no_case
0283               , is_same<bool_policies<T>, Policies>
0284             >
0285           , literal_bool_parser<T, no_case_bool_policies<T> >
0286           , literal_bool_parser<T, Policies> >::type
0287         result_type;
0288
0289         template <typename Terminal>
0290         result_type operator()(Terminal const& term, unused_type) const
0291         {
0292             return result_type(fusion::at_c<0>(term.args));
0293         }
0294     };
0295
0296     ///////////////////////////////////////////////////////////////////////////
0297     template <typename Modifiers, typename A0>
0298     struct make_primitive<
0299           terminal_ex<tag::lit, fusion::vector1<A0> >
0300         , Modifiers, typename enable_if<is_same<A0, bool> >::type>
0301       : make_literal_bool<bool, Modifiers> {};
0302
0303     ///////////////////////////////////////////////////////////////////////////
0304     template <typename Modifiers>
0305     struct make_primitive<tag::false_, Modifiers>
0306       : make_predefined_direct_bool<bool, Modifiers, false>
0307     {};
0308
0309     template <typename Modifiers>
0310     struct make_primitive<tag::true_, Modifiers>
0311       : make_predefined_direct_bool<bool, Modifiers, true>
0312     {};
0313
0314     ///////////////////////////////////////////////////////////////////////////
0315     template <typename T, typename Policies, typename Modifiers>
0316     struct make_primitive<
0317         tag::stateful_tag<Policies, tag::bool_, T>, Modifiers>
0318       : make_bool<T, Modifiers, Policies> {};
0319
0320     template <typename T, typename Policies, typename A0, typename Modifiers>
0321     struct make_primitive<
0322         terminal_ex<tag::stateful_tag<Policies, tag::bool_, T>
0323       , fusion::vector1<A0> >, Modifiers>
0324       : make_direct_bool<T, Modifiers, Policies> {};
0325
0326     ///////////////////////////////////////////////////////////////////////////
0327     template <typename Modifiers>
0328     struct make_primitive<tag::bool_, Modifiers>
0329       : make_bool<bool, Modifiers> {};
0330
0331     template <typename Modifiers, typename A0>
0332     struct make_primitive<
0333         terminal_ex<tag::bool_
0334       , fusion::vector1<A0> >, Modifiers>
0335       : make_direct_bool<bool, Modifiers> {};
0336 }}}
0337
0338 #endif