What is Luqum
###############

Luqum stands for LUcene QUery Manipolator.

It features a python library with a parser for  the `Lucene Query DSL`_ as found in
`Solr`_ `query syntax`_ or
`ElasticSearch`_ `query string`_

From the parser it builds a tree (see :ref:`tutorial-parsing`).

This tree can eventually be manipulated
and then transformed back into a query string,
or used to generate other form of query.

In particular, luqum ships with
a utility to transform a lucene query
into a query using Elasticsearch query DSL language (in json form).
(see :ref:`tutorial-elastic`)

You may use this to:

* make some sanity check on query
* make your own check on query (eg. forbid certain fields)
* replace some expressions in query
* pretty print a query
* inject queries in queries
* extend lucene query language semantics

The parser is built using `PLY`_.

Luqum is dual licensed under Apache2.0 and LGPLv3.

.. warning::

   While used in production by our team for some time,
   this library is still a work in progress and also lacks some features.

   Contributions are welcome.

.. _`Lucene Query DSL`: https://lucene.apache.org/core/3_6_0/queryparsersyntax.html
.. _`Solr`: http://lucene.apache.org/solr/
.. _`query syntax`: https://wiki.apache.org/solr/SolrQuerySyntax
.. _`ElasticSearch`: https://www.elastic.co/products/elasticsearch
.. _`query string`: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html
.. _`PLY`: http://www.dabeaz.com/ply/ply.html