util-tuple.hpp

/*
  UTIL-TUPLE.hpp  -  helpers and convenience shortcuts for working with tuples

   Copyright (C)
     2023,            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 UTIL_TUPLE_H
#define UTIL_TUPLE_H


#include <tuple>
#include <utility>



namespace util {
  
  namespace { // recursive builder helper to unpack a sequence...
    
    template<size_t N>
    using cnt_ = std::integral_constant<size_t, N>;
    
    template<class SEQ>
    inline auto
    _buildSeqTuple (cnt_<0>, SEQ&&)
    {
      return std::tuple<>{};
    }
    
    template<size_t N, class SEQ>
    inline auto
    _buildSeqTuple (cnt_<N>, SEQ&& iter)
    {
      auto prefixTuple = std::tie (*iter);
      ++iter;
      return std::tuple_cat (prefixTuple, _buildSeqTuple (cnt_<N-1>{}, std::forward<SEQ> (iter)));
    }
  }//(End) unpacking helper
  
  
  template<size_t N, class SEQ>
  auto
  seqTuple (SEQ&& iter)
  {
    return _buildSeqTuple (cnt_<N>{}, std::forward<SEQ> (iter));
  }
  
  
} // namespace util
#endif /*UTIL_TUPLE_H*/