/*
  DOMAIN.hpp  -  represent the value domain of parameters

   Copyright (C)
     2026             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.

*/


/** @file domain.hpp
 ** Specification of a base type and a value domain for parameters.
 ** A Domain descriptor implicitly also encodes the concrete value type
 ** and exposes a set of virtual functions to handle all supported value conversions.
 ** Implementing this interface creates a conversion matrix and allows to implement
 ** generic conversions by double-dispatch. Since virtual interfaces must be complete
 ** at compile time however, such an approach requires to define a finite set of
 ** supported parameter value types, which seems adequate, since the universe
 ** of possible values is limited anyway: elementary values in parameters
 ** must be primitive base types that can be created and destroyed
 ** without side effect. Relying on the further features of
 ** the parameter type system, compound types (vectors)
 ** and limited sub-scales can be defined.
 ** 
 ** @todo WIP-WIP-WIP this is a draft and placeholder, as of 2026
 */


#ifndef LIB_PAR_DOMAIN_H
#define LIB_PAR_DOMAIN_H




namespace lib {
namespace par {
  
  
  
  /**
   * Interface: mark the allowed value domain of a parameter value.
   * The identity of the actual implementation can be used as type descriptor,
   * since all concrete full base domains are registered at compile time; the
   * virtual Domain interface exposes the possible conversions.
   * @todo 7/2026 not clear if we can support all conversions unconditionally,
   *       or if some notion of an _impossible conversion_ is required. It is
   *       clear however, that the access to an actual parameter **must fail**
   *       at compile time, if a sensible conversion can not be provided.
   */
  class Domain
    {
    public:
      virtual ~Domain();  ///< this is an interface
    };
  
  
  
}} // namespace lib::par
#endif /*LIB_PAR_DOMAIN_H*/