CQL version 6.1 release notes

For CQL version 6.1 features, see what's new in CQL 6.1. For CQL version 6.0.5, see CQL 6.0.5 documentation

CQL version 6.0.5 release notes

  • We thank Robert Gamble generally for developing a meticulously programmed code suite, which has improve CQL greatly throughout.
  • An command line option -outputbuffer has been added. This option must be followed by a positive integer denoting the maximum number of bytes in a single output PGN game (the current default is 105000). This option is experimental and not supported.
  • The two-piece-cycle.cql CQL file, which illustrates regular expression usage in line , was added to the examples.

CQL version 6.0.4 release notes

CQL version 6.0.3 release notes

    (bug fixes) This version is primarily a bug-fix release. We thank Robert Gamble for his assistance with this release.
  • When a transform's argument is a numeric filter, then the transform filter itself is numeric with value equal to the maximum of the values of the matching transforms of its argument.
  • The transform documentation has been substantially rewritten. In addition to the introduction to transforms, there is now a more formal description. Each transform filter now has its own page.
  • comment and message now accept filters that have no value as argument. If the filter has no value, then <true> or <false> is output, depending on whether the filter matches. For example
    comment ("check is: " check)
  • max and min now accept more than two arguments.
  • Some generic improvements to smart comments were made.
  • Transform filters are more efficient in many cases, and are much better at avoiding the generation of redundant transforms.
  • Transforms are now documented as supporting the count keyword. The use of range parameters to transform filters is now deprecated.
  • The notransform filter was added.
  • The currenttransform keyword in message and comment was added.

CQL version 6.0.2 release notes

Release Notes for CQL version 6.0

This table below is a partial list of changes from CQL version 5.2 to CQL version 6.0. It is not complete due to the large number of changes that were made.

We thank Robert Gamble for his assistance in finding and fixing numerous bugs in version 6.0.

Note that there were also some important changes from CQL version 5.1 to CQL version 5.2. If you are still using CQL version 5.1, read the release notes for CQL 5.2 before reading these release notes. CQL 6 also runs much faster than previous versions, particularly on complex CQL files. (On an 8-core machine, we typically see speedups of a factor of between 10 and 80 compared to CQL 5.2, depending on the exactly CQL file and PGN database). CQL 6 is also substantially more expressive and compact than previous versions of CQL.


multi-threaded execution cql foo.cql CQL by default runs in multiple threads
Variable names need not start with a dollar sign checkers=A attack k A variable name can be any sequence of allowed characters and need not start with a dollar sign
Variables can hold integers, sets of squares or positions Attacks=A attacks .
x = #Attacks
y=find check
More powerful variables
Arithmetic expressions power A * 3<power a basic integer arithmetic and relational expressions
legal move checking move legal enpassant move filter supports legal and pseudolegal move computation (as well as castling and capture)
functions function forks(x){[rbnqk] attackedby x>1} user-defined functions
if if pin through a then x else y if/then/else statments
many more command line features cql -variations foo.cql arbitrary filters on the command line
many new command line options
pawn structure filters passedpawns
sort connectedpawns
pawn structure filters
run cql without a CQL file cql -i mydatabase.pgn -cql stalemate -cql btm -cql r when CQL file is missing, use cql(). as file
FEN support cql -fen 8/5kp1/p5N1/P4Pp1/6P1/PKP5/1B1r4/8 -i foo.pgn find positions in FEN notation, in CQL file or using -fen command line option
pin supportpin through A>1 Find pins
c-style comments check // the position is check
/* this line is ignored */
Anything after // on a line in a CQL file is ignored. Anything between /* and */ is ignored.
xray xray (A a k) Rays where first argument attacks second (renamed from ray attack)
persistent variables persistent NStalemates = NStalemates +1 persistent variables retain their value between games. They can be used for statistics
echo echo(s t) s&t==. simpler and more powerful replacement for old relation syntax