// PropStat.h

#ifndef PropStat_H
#define PropStat_H

// Class to describe the result of a propagation.
//
// Class is constructed in a state indicating failure.
//
// Call set_same() or set_path_distance(s) if propagation is
// successful.
//
// Obselete interface:
// Call either set_forward(), set_backward() or set_same() if 
// propagation is successful.

#include <iosfwd>

namespace trf {

class PropStat {

private:
  bool _success;
  double _s;

public:

  // constructor
  // Defult state indicates failure.
  // Call one of set
  PropStat();

  // set the distance of propagation
  void set_path_distance(double s);

  // set successful propagation forward
  // This method is obselete and will be dropped (25aug98)
  void set_forward();

  // set successful propagation backward 
  // This method is obselete and will be dropped (25aug98)
  void set_backward();

  // set successful propagation to same point
  void set_same();

  // was propagation successful?
  bool success() const;

  // did track move forward?
  bool forward() const;

  // did track move backward?
  bool backward() const;

  // did track propagate succesfully to the same position?
  bool same() const;

  // return the propagation path distance.
  double path_distance() const;

};

}  // end namespace trf

// output stream
std::ostream&
operator<<(std::ostream& stream, const trf::PropStat& pst);

#endif