The . characterThe
.-filter is a set filter that represents the 64 squares of the chessboard. It matches any position.
.-filter can be used as a way to accept "any position" within a line filter:
line --> . --> Ra3matches a position where the white rook is on a3 following the current move.
As a set, the
.-filter is useful where one explicitly wants to consider all squares.
.-filter is used throughout the examples. One instance is
(found from CQL file: maxqueenattack.cql)
shows a position where the white queen attacks the maximum 27 squares. It was found from the cql file maxqueenattack.cql .