tree-mutator-noop-binding.hpp

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/*
  TREE-MUTATOR-NOOP-BINDING.hpp  -  diff::TreeMutator implementation building block

  Copyright (C)         Lumiera.org
    2018,               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 LIB_DIFF_TREE_MUTATOR_NOOP_BINDING_H
#define LIB_DIFF_TREE_MUTATOR_NOOP_BINDING_H


#include "lib/error.hpp"
#include "lib/diff/gen-node.hpp"
#include "lib/diff/tree-mutator.hpp"

#include <type_traits>

namespace lib {
namespace diff{

  namespace { // Mutator-Builder decorator components...
    
    
    class BlackHoleMutation
      : public TreeMutator
      {
        
      public:
        BlackHoleMutation () = default;
        
        
        /* ==== TreeMutator API ==== */
        
        using Elm  = GenNode const&;
        using Buff = TreeMutator::Handle;
        
        bool hasSrc()                override { return true; }  
        
        bool injectNew (Elm)         override { return true; }  
        bool matchSrc (Elm)          override { return true; }  
        bool acceptSrc (Elm)         override { return true; }  
        bool accept_until (Elm)      override { return true; }  
        bool findSrc (Elm)           override { return true; }  
        bool assignElm (Elm)         override { return true; }  
        
        bool
        mutateChild (Elm, Buff buff) override                   
          {
            buff.emplace (BlackHoleMutation());
            return true;
          }
      };
    
    
    
    template<class PAR>
    inline auto
    Builder<PAR>::ignoreAllChanges()
    {
      static_assert (std::is_same<PAR, TreeMutator>()
                    ,"ignoreAllChanges() must be used as bottom layer.");
      
      return Builder<BlackHoleMutation> (BlackHoleMutation{});
    }
    
    
    
  }//(END)Mutator-Builder decorator components...
  
}} // namespace lib::diff
#endif /*LIB_DIFF_TREE_MUTATOR_NOOP_BINDING_H*/