scope-query.hpp

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/*
  SCOPE-QUERY.hpp  -  query to discover the contents of a container-like part of the model
 
   Copyright (C)
     2009,            Hermann Vosseler <Ichthyostega@web.de>
 
 **Lumiera** 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. See the file COPYING for further details.
 
*/
 
 
#ifndef STEAM_MOBJECT_SESSION_SCOPE_QUERY_H
#define STEAM_MOBJECT_SESSION_SCOPE_QUERY_H
 
 
#include "steam/mobject/placement.hpp"
#include "common/query/query-resolver.hpp"
#include "lib/format-string.hpp"
 
#include <functional>
 
 
namespace steam {
namespace mobject {
namespace session {
  
  using std::bind;
  using std::function;
  using std::placeholders::_1;
  
  using lumiera::Goal;
  using lumiera::Query;
  
  
  
  template<class MO>
  class DiscoveryQuery
    : public Query<Placement<MO>>
    {
      using _Query = Query<Placement<MO>>;
      
      
    public:
      using iterator      = _Query::iterator;
      using ContentFilter = function<bool(PlacementMO const&)>;
      
      
      ContentFilter
      contentFilter () const
        {
          return buildContentFilter();
        }
 
    protected:
      virtual ContentFilter  buildContentFilter()  const  =0;
      
      
      
      
      DiscoveryQuery ()
        : _Query (_Query::defineQueryTypeID (Goal::DISCOVERY)
                 , lib::QueryText(""))  //  syntactic representation supplied on demand
        { }
      
    private:
      DiscoveryQuery const& operator=(DiscoveryQuery const&);
    };
  
  
  enum ScopeQueryKind
    { CONTENTS = 0      
    , CHILDREN          
    , PARENTS           
    , PATH              
    };
  
  
  template<class MO>
  class ScopeQuery
    : public DiscoveryQuery<MO>
    {
      using _Parent = DiscoveryQuery<MO>  ;
      using _Query = Query<Placement<MO>>;
      
      
      PlacementMO::ID    startPoint_;
      ScopeQueryKind    to_discover_;
      
    public:
      using iterator      = _Parent::iterator     ;
      using ContentFilter = _Parent::ContentFilter;
      
      
      ScopeQuery (PlacementMO  const& scope,
                  ScopeQueryKind direction)
        : startPoint_(scope)
        , to_discover_(direction)
        { }
      
      
      
      PlacementMO::ID const&
      searchScope ()  const
        {
          return startPoint_;
        }
      
      ScopeQueryKind
      searchDirection ()  const
        {
          return to_discover_;
        }
      
      
      
    private:
      ContentFilter
      buildContentFilter()  const
        {
          return bind (&PlacementMO::isCompatible<MO>, _1 );
        }
      
      lib::QueryText
      buildSyntacticRepresentation()  const
        {
          using util::_Fmt;
          TODO ("valid syntactic representation of scope queries");
          return lib::QueryText (_Fmt ("scope(X, %08X), scopeRelation(X, %d)")
                                      % hash_value(searchScope())        
                                      % uint(searchDirection()));        
        }
    };
  
  
  template<class MO>
  struct ContentsQuery
    : ScopeQuery<MO>
    {
      ContentsQuery (PlacementMO  const& scope)
        : ScopeQuery<MO> (scope, CONTENTS)
        { }
      
    };
  
  
  template<class MO>
  struct PathQuery
    : ScopeQuery<MO>
    {
      PathQuery (PlacementMO  const& scope)
        : ScopeQuery<MO> (scope, PARENTS)
        { }
      
    };
  
  
 
 
}}} // namespace steam::mobject::session
#endif