Module hexe_core::castle [−] [src]

Functionality dealing with castling in chess.

What is Castling?

In chess, castling is a special move performed by a king and a rook. Castling can only be done under certain conditions.

For example, a piece can't be moved in a castle if it has been moved previously. You can use the Rights type to keep track of this case:

If a king has moved, both castle rights for its color must be cleared
If a rook has moved, the castle right for its color and board side must be cleared

Before:         | After:
r . + . k . + r | . . k r . . . r
. . . . . . . . | . . . . . . . .
. . . . . . . . | . . . . . . . .
. . . . . . . . | . . . . . . . .
. . . . . . . . | . . . . . . . .
. . . . . . . . | . . . . . . . .
. . . . . . . . | . . . . . . . .
R . + . K . + R | R . . . . R K .

In the before frame, kings and rooks are in their initial positions. Kings may be moved to the indicated (+) squares. In the after frame, White has castled kingside and Black has castled queenside.

Notice that the king can only move a maximum of two squares when castling, regardless of which board side.

Modules

path	The paths between the rook and king for each castling right.

Structs

FromStrError	The error returned when `Rights::from_str` fails.
Rights	Castle rights for a chess game.

Enums

Right	An individual castle right for a chess game.
Side	A side used to castle.