CONCEPT/predicate.h

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// -*- Mode: C++; tab-width: 2; -*-
// vi: set ts=2:
//

#ifndef BALL_CONCEPT_PREDICATE_H
#define BALL_CONCEPT_PREDICATE_H

#ifndef BALL_COMMON_GLOBAL_H
# include <BALL/COMMON/global.h>
#endif

#include <functional>

namespace BALL 
{
  using std::unary_function;
  using std::binary_function;
    
  
  template <typename T> 
  class UnaryPredicate 
    : public unary_function<T, bool> 
  {
    public:
    virtual ~UnaryPredicate() {}

    virtual bool operator() (const T& /* x */) const
      ;
  };

  template <typename T1, typename T2> 
  class BinaryPredicate 
    : public binary_function<T1, T2, bool> 
  {
    public:

    virtual bool operator() (const T1& x, const T2& y) const
      ;

    virtual ~BinaryPredicate() {}
  };

  template <typename T> 
  bool UnaryPredicate<T>::operator() (const T& /* x */) const
    
  {
    return true;
  }

  template <typename T1, typename T2> 
  bool BinaryPredicate<T1, T2>::operator() (const T1&, const T2&) const
    
  {
    return true;
  }
} // namespace BALL


#endif // BALL_CONCEPT_PREDICATE_H