CQL Technical Description

The technichal description is not a precondition for the usage of the search functions in Scidb.

• Index
• Display
• The CQL-S standard

Index

• Syntax
• Transformations
• The match list
• The position list
• The relation list
• Tagging
• Examples
• File format

display

Per default graphical figurine for the notation of chess pieces will be used, due to internalization reasons. The CQL editor is also working with graphical figurine, although the CQL files will be saved with the corresponding English letters:

• ♔	=	K	=	white king
  ♕	=	Q	=	white queen
  ♖	=	R	=	white rook
  ♗	=	B	=	white bishop
  ♘	=	N	=	white knight
  ♙	=	P	=	white pawn
  ♚	=	k	=	black king
  ♛	=	q	=	black queen
  ♜	=	r	=	black rook
  ♝	=	b	=	black bishop
  ♞	=	n	=	black knight
  ♟	=	p	=	black pawn

If you prefer to see piece letters, please select one of the options:

The CQL-S standard

The CQL-S standard is developed to cover all functions of Scidb also inside the game search and position search. For fulfilling the CQL-S standard all keywords have to be implemented. But the features for other chess variants must not be supported (this means, for example, that :mustcapture will not be satisfied ever). The CQL parser should use the file header to detect whether a CQL-S script can be executed (⇒ file format).

CQL-S is almost 100% backward compatible with just two exceptions:

1. In CQL 1.0 :flipcolor does not apply to :result (inside position list). This may well be considered as an error. In CQL-S :flipcolor will also do a color flip transformation in :result.
2. In CQL 1.0 the start position will not be considered when searching. In CQL-S also the start position will be considered when searching for a position, and will match where appropriate. Including the start position is essential for position search in a chess database.