common/configrules.hpp

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/*
  CONFIGRULES.hpp  -  interface for rule based configuration
 
  Copyright (C)         Lumiera.org
    2008,               Hermann Vosseler <Ichthyostega@web.de>
 
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
*/


#ifndef LUMIERA_CONFIGRULES_H
#define LUMIERA_CONFIGRULES_H

#include "common/p.hpp"
#include "common/query.hpp"
#include "common/meta/generator.hpp"
#include "common/singletonsubclass.hpp"

//TODO: is it sensible to bring in the types explicitly here? (it's not necessary, but may be convenient...)
#include "proc/mobject/session/track.hpp"
#include "proc/asset/procpatt.hpp"
#include "proc/asset/pipe.hpp"
#include "proc/asset/track.hpp"

#include <string>



namespace lumiera
  {
  using std::string;
  using lumiera::P;

  
  
    
  namespace query
    {
    // The intention is to support the following style of Prolog code
    //
    //  resolve(O, Cap) :- find(O), capabilities(Cap).
    //  resolve(O, Cap) :- make(O), capabilities(Cap).
    //  capabilities(Q) :- call(Q).
    //  
    //  stream(T, mpeg) :- type(T, track), type(P, pipe), resolve(P, stream(P,mpeg)), place_to(P, T).
    //
    // The type guard is inserted auomatically, while the predicate implementations for
    // find/1, make/1, stream/2, and place_to/2 are to be provided by the target types.
    //
    // As a example, the goal ":-retrieve(T, stream(T,mpeg))." would search a Track object, try to
    // retrieve a pipe object with stream-type=mpeg and associate the track with this Pipe. The
    // predicate "stream(P,mpeg)" needs to be implemented (natively) for the pipe object.
    
    class Resolver
      {
        
      };
    
    
    template
      < const Symbol SYM,            // Predicate symbol
        typename SIG = bool(string) //  Signature
      >
    class Pred
      {
        
      };
      
    template<class TY>
    class TypeHandler
      {
        static const TY NIL;
        
        template<Symbol SYM, typename SIG>
        TY find (Pred<SYM,SIG> capability);
        
        template<Symbol SYM, typename SIG>
        TY make (Pred<SYM,SIG> capability, TY& refObj =NIL);
      };
    
    template<class TY>
    class QueryHandler
      {
      protected:
        virtual ~QueryHandler()  { }
      public:
        virtual bool resolve (P<TY>& solution, const Query<TY>& q) = 0;
      };

    // TODO: the Idea is to provide specialisations for the concrete types
    //       we want to participate in the ConfigRules system....
    //       Thus we get the possibility to create a specific return type,
    //       e.g. return a P<Pipe> but a Placement<Track>, using the appropriate factory.
    //       Of course then the definitions need to be split up in separate headers.
      
      
      
      
      
    template<typename TYPES>
    class ConfigRules
      : public typelist::InstantiateForEach<TYPES, QueryHandler>
      {
      protected:
        ConfigRules ()         {}
        virtual ~ConfigRules() {} 
        
      public:
        // TODO: find out what operations we need to support here for the »real solution« (using Prolog)
      };
      

    
    
    LUMIERA_ERROR_DECLARE (CAPABILITY_QUERY);  
  
  } // namespace query
  
  
  
  
  
  /* ============= global configuration ==================== */
  
  typedef lumiera::typelist::Types < mobject::session::Track
                                   , asset::Track
                                   , asset::Pipe
                                   , const asset::ProcPatt
                                   > ::List
                                     InterfaceTypes;
  
  class ConfigRules
    : public query::ConfigRules<InterfaceTypes>
    {
  
    public:
      static SingletonSub<ConfigRules> instance;
      
    };
  
  
  
    
  namespace query
    {
    
    void setFakeBypass(string const& q);
    bool isFakeBypass (string const& q);
    
  } // namespace query
  
} // namespace lumiera
#endif

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