On 27/11/2010 03:27, Andrei Alexandrescu wrote:
http://oredev.org/2010/sessions/c-s-greatest-mistakes
Andrei
Looking at the bit about enums....
Java enums and C, D, etc. enums have their pros and cons. I suppose the
main advantages of C enums are:
- lightweight
- can also be used as bit sets
You could argue that bit sets ought to be a separate type. But this
precludes uses that combine "proper" enum use with a bit flag or two.
Take, from one of my programs,
enum Piece : byte {
EMPTY, PAWN, BISHOP, KNIGHT,
ROOK_CANNOT_CASTLE, ROOK_CAN_CASTLE, QUEEN, KING,
BLACK = 8,
LAST = Piece.BLACK | KING
}
The first 8 values are mutually exclusive, BLACK is a bit flag, and LAST
is just a marker value. But the compiler doesn't stop you doing silly
stuff like Piece.PAWN | Piece.BISHOP. Maybe someone can come up with a
better way of doing this....
Java enums preclude having an array indexed by them. I suppose the
ability to store data in the enum objects was meant to make up for this.
But I recall that somebody in one company I briefly worked for didn't
really like Java enums because of this complexity....
Stewart.
