//// Constants
////
-/// Note: If OnePly is changed, the constant HistoryMax in history.h should
-/// probably also be changed.
-
const Depth OnePly = Depth(2);
inline void operator+= (Depth &d1, Depth d2) { d1 += int(d2); }
inline Depth operator- (Depth d, int i) { return Depth(int(d) - i); }
inline Depth operator- (Depth d1, Depth d2) { return Depth(int(d1) - int(d2)); }
-inline void operator-= (Depth & d, int i) { d = Depth(int(d) - i); }
+inline void operator-= (Depth &d, int i) { d = Depth(int(d) - i); }
+inline void operator-= (Depth &d1, Depth d2) { d1 -= int(d2); }
inline Depth operator* (Depth d, int i) { return Depth(int(d) * i); }
inline Depth operator* (int i, Depth d) { return Depth(int(d) * i); }
inline void operator*= (Depth &d, int i) { d = Depth(int(d) * i); }