bishoppawnpinrelation.cql; bishoppawnpinrelation.cql can be downloaded here.
; In the mainline, a Black bishop attacks the White King, but White ; interposes a pawn. ; In the variation, the pawn is unable to interpose - either it is ; missing or it has moved. ; All the other pieces apart from the pawn haven't moved. cql(input heijden.pgn variations) wtm mainline piece $bishop in b ray attack ($bishop K) piece $pawn in P move primary from $pawn to _ relation variation ray attack ($bishop K) not between ($bishop K) on up 1 P or _ on up 1 Pa-h2 (sourcesquares not $pawn targetsquares not $pawn mismatch 0)