MetaUtils.h

Go to the documentation of this file.

#ifndef LARCOREALG_COREUTILS_METAUTILS_H
#define LARCOREALG_COREUTILS_METAUTILS_H


// C/C++ standard libraries
#include <type_traits>


namespace util {
  
  
  //--- BEGIN MetaprogrammingBase ----------------------------------------------
  
  namespace details {
    
    template <typename T>
    struct ClassNameStaticDumper;
    
  } // namespace details
  
  
  //----------------------------------------------------------------------------
  template <typename T>
  struct self_type { using type = T; };
  
  template <typename T>
  using self_t = typename self_type<T>::type;
  
  
  //----------------------------------------------------------------------------
  template <typename>
  struct always_false_type: public std::false_type {};
  
  
  //----------------------------------------------------------------------------
  template <typename>
  constexpr bool always_false_v = false;
  
  
  template <typename>
  struct always_true_type: public std::true_type {};
  
  
  template <typename>
  constexpr bool always_true_v = true;
  
  
  // will be present in C++17 as std::bool_constant
  template <bool Value>
  using bool_constant = std::integral_constant<bool, Value>;
  
  // will be present in C++17 as std::negation
  template <typename BoolTrait>
  using negation = bool_constant<!BoolTrait::value>;
  
  template <typename A, typename B>
  using is_not_same = negation<std::is_same<A, B>>;
  
  
  // @{
  template <typename T>
  void staticDumpClassName();
  
  template <typename T>
  void staticDumpClassName(T) { staticDumpClassName<T>(); }
  // @}
  
  
  //--- END MetaprogrammingBase ------------------------------------------------
  
  
} // namespace util


//------------------------------------------------------------------------------
//---  Template implementation
//------------------------------------------------------------------------------
namespace util {
  
  //----------------------------------------------------------------------------
  namespace details {
    
    template <typename T>
    struct ClassNameStaticDumper {
      static_assert(
        util::always_false_type<T>(),
        "ClassNameStaticDumper<T>: look for T in the error message context"
        );
    }; // struct ClassNameStaticDumper
    
  } // namespace details
  
  
  //----------------------------------------------------------------------------
  template <typename T>
  void staticDumpClassName() { (void) details::ClassNameStaticDumper<T>(); }
  
  
  //----------------------------------------------------------------------------
  
} // namespace util


//------------------------------------------------------------------------------

#endif // LARCOREALG_COREUTILS_METAUTILS_H