This module parses a query string into a data structure to be handled by
external search engines. For examples of such engines, see the
File::Tabular manpage and the Search::Indexer manpage.

The query string can contain simple terms, "exact phrases", field names and
comparison operators, '+/-' prefixes, parentheses, and boolean connectors.

The parser can be parameterized by regular expressions for specific notions
of "term", "field name" or "operator" ; see the the new manpage method. The
parser has no support for lemmatization or other term transformations :
these should be done externally, before passing the query data structure to
the search engine.