Type selectivity is provided by means of the captureMatrix, possibly in combination with the apostrophy in the XBetza to restrict it to a subset of the moves. I haven't encountered any case yet that could not be handled this way.
But what if the qualification only affects one of a group of possible moves? In this case, the opening move of a Pawn, which could capture anything with its conventional capture but has a special initial move only for capturing nearby enemy Pawns.
But what if the qualification only affects one of a group of possible moves? In this case, the opening move of a Pawn, which could capture anything with its conventional capture but has a special initial move only for capturing nearby enemy Pawns.