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Does XBetza allow defining pieces that capture by stopping in the square just before the captured piece?

yamcfyambK comes close to defining a Queen that does that, aka Rococo's Advancer; it is, however, what Charles Gilman called a ‘Strict’ advancer, in that it also can't approach a friendly piece (as doing so would capture it), as well as (as a byproduct of the implementation) being unable to approach the edge once it's left it. Adding mQ would lift those restrictions at the expense of making the capture upon advance optional. Idk if it's possible to do better without extending the notation though

Another question I have is, does 0 have any meaning when used as a piece's range? If not, perhaps it could be used to indicate that a piece must move as far as possible in whichever direction it goes.

Afaict (istr it was declared explicilty at some point though idr where) 0 corresponds to unlimited range. gabQ handles going as far as possible provided there's a piece in the way, but is subject to the same edge case(!) as the advancer wrt the boundaries of the board — again I doubt it's possible to contrive a way around that without dedicated extensions