JEnumeration.hh

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#ifndef __JLANG__JENUMERATION__
#define __JLANG__JENUMERATION__

#include <ostream>

#include "JLang/JAssert.hh"
#include "JLang/JType.hh"
#include "JLang/JTypeID.hh"
#include "JLang/JTypeList.hh"


/**
 * \author mdejong
 */

namespace JLANG {}
namespace JPP { using namespace JLANG; }

namespace JLANG {

  /**
   * Test presence of data type identifier in labelled type list.
   */
  template<class T, int ID>
  struct JHasID
  {
    static const bool value = (JTypeID<T>::ID == ID);
  };
  

  /**
   * Recursive test of presence data type identifier in labelled type list.
   */
  template<class JHead_t, class JTail_t, int ID>
  struct JHasID<JTypeList<JHead_t, JTail_t>, ID>
  {
    static const bool value = (JHasID<JHead_t, ID>::value  ||  
                               JHasID<JTail_t, ID>::value);
  };


  /**
   * Enumeration of single data type.
   */
  template<class T>
  struct JEnumeration
  {
    /**
     * Get label of given data type.
     *
     * \param  type              data type
     * \return                   label
     */
    static inline JLabel_t getLabel(const JType<T>& type) 
    { 
      return JLabel_t(JTypeID<T>::ID, 
                      JTypeID<T>::getName(), 
                      JTypeID<T>::getVersion());
    }


    /**
     * Get label of given object.
     *
     * \param  object            object
     * \return                   label
     */
    static inline JLabel_t getLabel(const T& object) 
    { 
      return getLabel(JType<T>());
    }


    /**
     * Print enumeration.
     *
     * \param  out               output stream
     * \return                   output stream
     */
    static std::ostream& print(std::ostream& out)
    {
      out << getLabel(JType<T>()) << std::endl;

      return out;
    }
  };


  /**
   * Enumeration of multiple data types.
   *
   * The uniqueness of each data type and identifier in the type list is verified; 
   * failure causes a compiler error. 
   */
  template<class JHead_t, class JTail_t>
  struct JEnumeration< JTypeList<JHead_t, JTail_t> > :
    public JEnumeration<JHead_t>,
    public JEnumeration<JTail_t>,
    public virtual JAssert<!JHasType<JTail_t,         JHead_t>     ::value && 
                           !JHasID  <JTail_t, JTypeID<JHead_t>::ID>::value>
  {
    using JEnumeration<JHead_t>::getLabel;
    using JEnumeration<JTail_t>::getLabel;


    /**
     * Print enumeration.
     *
     * \param  out               output stream
     * \return                   output stream
     */
    static std::ostream& print(std::ostream& out)
    {
      JEnumeration<JHead_t>::print(out);
      JEnumeration<JTail_t>::print(out);

      return out;
    }
  };


  /**
   * Terminator class of recursive JEnumeration class.
   */
  template<class JHead_t>
  struct JEnumeration< JTypeList<JHead_t, JNullType> > :
    public JEnumeration<JHead_t>
  {};
}

#endif