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Chess Query Language (CQL) parser
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.. contents::


Description
===========

This package provides a parser for Chess Query Language (`CQL`_).

The documentation for `CQL version 6.0.4`_ as found in first half of 2020, plus `CQL version 6.1`_ and `CQL version 6.2`_ as found in mid-2024, was used as a reference.

`CQLi`_ provides an alternative implementation of CQL-6.1 and a '-parse' option which gives output more easily compared with ChessQL output.

This package does not implement an evaluator to find games in a `PGN`_ file which match a query.


Installation Instructions
=========================

This package is available on PyPI so can be installed by typing

   python -m pip install --user chessql

at the command prompt.

See `Python`_ and `pip`_ documentation for alternatives and platform-specific points.


Use
===

Function core.parser.parse(<string>) returns a QueryContainer instance with the result of parsing a string usually read from a <*>.cql file.

Function core.parser.parse_command_line_query() returns a QueryContainer instance with the result of parsing a command line usually passed to the CQL executable.


Notes
=====

Version 3.0 of Chessql is incompatible with earlier versions.

An evaluator for some CQL constructs is implemented in `ChessTab`_.


.. _Python: https://python.org
.. _pip: https://packaging.python.org/installing
.. _CQL: http://www.gadycosteff.com
.. _PGN: http://www6.chessclub/help/PGN-spec
.. _CQL version 6.0.4: http://www.gadycosteff.com/cql-0-4
.. _CQL version 6.1: http://www.gadycosteff.com/cql-6.1
.. _CQL version 6.2: http://www.gadycosteff.com/cql
.. _CQLi: https://cql64.com
.. _ChessTab: http://www.solentware.co.uk/download.html