x3/directive/confix.hpp

0001 /*=============================================================================
0002     Copyright (c) 2009 Chris Hoeppler
0003     Copyright (c) 2014 Lee Clagett
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
0009 #if !defined(BOOST_SPIRIT_X3_CONFIX_MAY_30_2014_1819PM)
0010 #define BOOST_SPIRIT_X3_CONFIX_MAY_30_2014_1819PM
0011
0012 #include <boost/spirit/home/x3/core/parser.hpp>
0013
0014 namespace boost { namespace spirit { namespace x3
0015 {
0016     template<typename Prefix, typename Subject, typename Postfix>
0017     struct confix_directive :
0018         unary_parser<Subject, confix_directive<Prefix, Subject, Postfix>>
0019     {
0020         typedef unary_parser<
0021             Subject, confix_directive<Prefix, Subject, Postfix>> base_type;
0022         static bool const is_pass_through_unary = true;
0023         static bool const handles_container = Subject::handles_container;
0024
0025         constexpr confix_directive(Prefix const& prefix
0026                          , Subject const& subject
0027                          , Postfix const& postfix) :
0028             base_type(subject),
0029             prefix(prefix),
0030             postfix(postfix)
0031         {
0032         }
0033
0034         template<typename Iterator, typename Context
0035                  , typename RContext, typename Attribute>
0036         bool parse(
0037             Iterator& first, Iterator const& last
0038             , Context const& context, RContext& rcontext, Attribute& attr) const
0039         {
0040             Iterator save = first;
0041
0042             if (!(prefix.parse(first, last, context, rcontext, unused) &&
0043                   this->subject.parse(first, last, context, rcontext, attr) &&
0044                   postfix.parse(first, last, context, rcontext, unused)))
0045             {
0046                 first = save;
0047                 return false;
0048             }
0049
0050             return true;
0051         }
0052
0053         Prefix prefix;
0054         Postfix postfix;
0055     };
0056
0057     template<typename Prefix, typename Postfix>
0058     struct confix_gen
0059     {
0060         template<typename Subject>
0061         constexpr confix_directive<
0062             Prefix, typename extension::as_parser<Subject>::value_type, Postfix>
0063         operator[](Subject const& subject) const
0064         {
0065             return { prefix, as_parser(subject), postfix };
0066         }
0067
0068         Prefix prefix;
0069         Postfix postfix;
0070     };
0071
0072
0073     template<typename Prefix, typename Postfix>
0074     constexpr confix_gen<typename extension::as_parser<Prefix>::value_type,
0075                typename extension::as_parser<Postfix>::value_type>
0076     confix(Prefix const& prefix, Postfix const& postfix)
0077     {
0078         return { as_parser(prefix), as_parser(postfix) };
0079     }
0080
0081 }}}
0082
0083 #endif