Ferdy wrote: ↑
Mon May 14, 2018 12:17 am
Is there a betza for a swap move? example,
e2e4 e7e5 g1f3 g8f6 d1f3
That d1f3 is a swap move, meaning the queen in d1 will go to f3 and the knight in f3 will go to d1. See image1.
I did define a modifier for capturing own pieces ('d' for 'destroy'), and I even think I implemented that in WinBoard. But it never occur to me to define something for swapping, and neither did I see it anywhere else. So I certainly did not implement anything like it in WinBoard; if it allows d1f3 at all, it will consider it a normal replacement capture.
I never even encountered a variant where you could capture your own pieces; I implemented side-effect capture capture of an own piece (i.e. in the non-final leg of a multi-leg move) as a non-royal castling. (The extended version of Omega Chess had this silly thing where a Queen could castle with a Rook.)
Of course I could make WinBoard interpret every capture of a friendly piece as a swap, rather than a capture. In the interactive diagram I actually did that for dropping pieces on top of an own piece: the latter then goes back into the hand. The letter 'd' would be a bit illogical for that, however.
I guess 'w' is still unused in XBetza; it could be used to indicate swapping with a friendly piece. But what if there is swapping with enemy pieces? I guess a more general way to indicate this kind of thing is to define 'u' as 'unload', i.e. leave behind what you captured or destroyed on an earlier leg. The swap could then be programmed as a 3-leg move, which would 'destroy' your own piece in the first leg, step back in the second leg to unload it on the from-square, and then again do the original move to the now-empty square. Similar t 'rifle capture' being defined as a two-leg move, the second leg undoing the first (except for the victim remaing gone). The 'i' (for 'iso') modifier can force equally-long slider legs, so caibR
for the Rifle-Rook: capture and again the same length back. Then daibuaibQ
would be "d
estroy with a Q
ueen move, a
gain the same length b
ack to u
nload the victim, and then a
gain the same length b
ack (w.r.t. previous leg). This would also allow swapping with enemies (use 'c' instead of 'd'), and more general 'catapult pieces'.