Taxonomy query language (tql)
-----------------------------

The taxonomy query language module implements a plugin for 
the 'search' and 'views' module. It provides a new tab
'Taxonomy' in the Drupal search and a new Views filter.

Use
---

If you have the 'tql' module and the search module enabled,
a 'Taxonomy' tab appears in the search where you can enter
a search query. 

If you have the 'tql' module and 'Views' enabled, a new
filter 'Taxonomy: Query' is available which can be used
to enter a query. It works best if it is exposed so users
can enter their own query.

Language capabilities
---------------------

The query language can combine query terms with different
operators: AND, OR, XOR and NOT. The operator AND can be
omited as it is the default if two terms are listed without
operator. The operator NOT can be abbreviated with a dash in
front of the term, i.e. '-term'. Brackets can be used to
form more complex queries. The following are example queries
and their verbose equivalents:

term1 term2                <=> term1 and term2
term1 or -term2            <=> term1 or not term2
term1 xor -(term2 -term3)  <=> term1 xor not (term2 and not term3)

Building the lexer and parser
-----------------------------

The module is shipped with a built lexer and parser and you dont
need to build it yourself. If you to build it yourself you need 
the following PEAR packages:

PEAR: http://pear.php.net/package/PEAR
PHP_LexerGenerator: http://pear.php.net/package/PHP_LexerGenerator
PHP_ParserGenerator: http://pear.php.net/package/PHP_ParserGenerator

Install PEAR and put the lexer and parser generators into a directory 
'PHP' inside the directory 'ast'. Then change to the 'ast' directory 
and call 'make' to build the lexer and parser.


Authors:
mtn: Query language parser
rötzi: Drupal integration
bherlig: Adaptions for Drupal 6, Origo integration