/**
 * This implements a CDMaybe.
 * This has either been set in the context or it has not.
 * T must have a default constructor and support assignment.
 */

#include "cvc4_private.h"

#pragma once

#include "context/cdo.h"
#include "context/context.h"

namespace CVC4 {
namespace context {

class CDRaised {
private:
  context::CDO<bool> d_flag;

public:
 CDRaised(context::Context* c)
 : d_flag(c, false)
 {}


  bool isRaised() const {
    return d_flag.get();
  }

  void raise(){
    Assert(!isRaised());
    d_flag.set(true);
  }

}; /* class CDRaised */

template <class T>
class CDMaybe {
private:
  typedef std::pair<bool, T> BoolTPair;
  context::CDO<BoolTPair> d_data;

public:
  CDMaybe(context::Context* c) : d_data(c, std::make_pair(false, T()))
  {}

  bool isSet() const {
    return d_data.get().first;
  }

  void set(const T& d){
    Assert(!isSet());
    d_data.set(std::make_pair(true, d));
  }

  const T& get() const{
    Assert(isSet());
    return d_data.get().second;
  }
}; /* class CDMaybe<T> */

}/* CVC4::context namespace */
}/* CVC4 namespace */