tree-mutator-noop-binding.hpp

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/*
  TREE-MUTATOR-NOOP-BINDING.hpp  -  diff::TreeMutator implementation building block
 
   Copyright (C)
     2018,            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 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*/