An html version of staircase.cql
; staircase.cql can be downloaded here.
;;This filter file looks for queen staircases
;;search for a queen staircase.
;;
;;The "shift" and the "flip" commands are used to take the given sequence
;;and make sure it can be started from any square and any direction
;;
;;The "flipcolor" command is used to make sure that it works with black queens too.
;; Because there is no :variations keyword, this only searches for staircases in the
;; main line.
;; Because of the presence of both :shift and :flip commands, this query takes a long time.
(match
:pgn heijden.pgn
:output out.pgn
(position
:sequence
((position Qa2)
(position)
(position Qb2)
(position)
(position Qb3)
(position)
(position Qc3)
(position)
(position Qc4))
:shift
:flip
:flipcolor
))