Ubuntu Manpage: Search::Xapian - Perl XS frontend to the Xapian C++ search library.

Provided by: libsearch-xapian-perl_1.2.25.0-1_amd64

NAME

       Search::Xapian - Perl XS frontend to the Xapian C++ search library.

SYNOPSIS

         use Search::Xapian;

         my $db = Search::Xapian::Database->new( '[DATABASE DIR]' );
         my $enq = $db->enquire( '[QUERY TERM]' );

         printf "Running query '%s'\n", $enq->get_query()->get_description();

         my @matches = $enq->matches(0, 10);

         print scalar(@matches) . " results found\n";

         foreach my $match ( @matches ) {
           my $doc = $match->get_document();
           printf "ID %d %d%% [ %s ]\n", $match->get_docid(), $match->get_percent(), $doc->get_data();
         }

DESCRIPTION

       This module wraps most methods of most Xapian classes. The missing classes and methods
       should be added in the future. It also provides a simplified, more 'perlish' interface to
       some common operations, as demonstrated above.

       There are some gaps in the POD documentation for wrapped classes, but you can read the
       Xapian C++ API documentation at <https://xapian.org/docs/apidoc/html/annotated.html> for
       details of these.  Alternatively, take a look at the code in the examples and tests.

       If you want to use Search::Xapian and the threads module together, make sure you're using
       Search::Xapian >= 1.0.4.0 and Perl >= 5.8.7.  As of 1.0.4.0, Search::Xapian uses
       CLONE_SKIP to make sure that the perl wrapper objects aren't copied to new threads -
       without this the underlying C++ objects can get destroyed more than once.

       If you encounter problems, or have any comments, suggestions, patches, etc please email
       the Xapian-discuss mailing list (details of which can be found at
       <https://xapian.org/lists>).

   EXPORT
       None by default.

:db

       DB_OPEN
           Open a database, fail if database doesn't exist.

       DB_CREATE
           Create a new database, fail if database exists.

       DB_CREATE_OR_OPEN
           Open an existing database, without destroying data, or create a new database if one
           doesn't already exist.

       DB_CREATE_OR_OVERWRITE
           Overwrite database if it exists.

:ops

       OP_AND
           Match if both subqueries are satisfied.

       OP_OR
           Match if either subquery is satisfied.

       OP_AND_NOT
           Match if left but not right subquery is satisfied.

       OP_XOR
           Match if left or right, but not both queries are satisfied.

       OP_AND_MAYBE
           Match if left is satisfied, but use weights from both.

       OP_FILTER
           Like OP_AND, but only weight using the left query.

       OP_NEAR
           Match if the words are near each other. The window should be specified, as a parameter
           to "Search::Xapian::Query::Query", but it defaults to the number of terms in the list.

       OP_PHRASE
           Match as a phrase (All words in order).

       OP_ELITE_SET
           Select an elite set from the subqueries, and perform a query with these combined as an
           OR query.

       OP_VALUE_RANGE
           Filter by a range test on a document value.

:qpflags

       FLAG_DEFAULT
           This gives the QueryParser default flag settings, allowing you to easily add flags to
           the default ones.

       FLAG_BOOLEAN
           Support AND, OR, etc and bracketed subexpressions.

       FLAG_LOVEHATE
           Support + and -.

       FLAG_PHRASE
           Support quoted phrases.

       FLAG_BOOLEAN_ANY_CASE
           Support AND, OR, etc even if they aren't in ALLCAPS.

       FLAG_WILDCARD
           Support right truncation (e.g. Xap*).

       FLAG_PURE_NOT
           Allow queries such as 'NOT apples'.

           These require the use of a list of all documents in the database which is potentially
           expensive, so this feature isn't enabled by default.

       FLAG_PARTIAL
           Enable partial matching.

           Partial matching causes the parser to treat the query as a "partially entered" search.
           This will automatically treat the final word as a wildcarded match, unless it is
           followed by whitespace, to produce more stable results from interactive searches.

       FLAG_SPELLING_CORRECTION
       FLAG_SYNONYM
       FLAG_AUTO_SYNONYMS
       FLAG_AUTO_MULTIWORD_SYNONYMS

:qpstem

       STEM_ALL
           Stem all terms.

       STEM_NONE
           Don't stem any terms.

       STEM_SOME
           Stem some terms, in a manner compatible with Omega (capitalised words and those in
           phrases aren't stemmed).

:enq_order

       ENQ_ASCENDING
           docids sort in ascending order (default)

       ENQ_DESCENDING
           docids sort in descending order

       ENQ_DONT_CARE
           docids sort in whatever order is most efficient for the backend

:standard

       Standard is db + ops + qpflags + qpstem

Version functions

       major_version
           Returns the major version of the Xapian C++ library being used.  E.g. for Xapian 1.0.9
           this would return 1.

       minor_version
           Returns the minor version of the Xapian C++ library being used.  E.g. for Xapian 1.0.9
           this would return 0.

       revision
           Returns the revision of the Xapian C++ library being used.  E.g. for Xapian 1.0.9 this
           would return 9.  In a stable release series, Xapian libraries with the same minor and
           major versions are usually ABI compatible, so this often won't match the third
           component of $Search::Xapian::VERSION (which is the version of the Search::Xapian XS
           wrappers).

Numeric encoding functions

sortable_serialise NUMBER
Convert a floating point number to a string, preserving sort order.

This method converts a floating point number to a string, suitable for using as a
value for numeric range restriction, or for use as a sort key.

The conversion is platform independent.

The conversion attempts to ensure that, for any pair of values supplied to the
conversion algorithm, the result of comparing the original values (with a numeric
comparison operator) will be the same as the result of comparing the resulting values
(with a string comparison operator). On platforms which represent doubles with the
precisions specified by IEEE_754, this will be the case: if the representation of
doubles is more precise, it is possible that two very close doubles will be mapped to
the same string, so will compare equal.

Note also that both zero and -zero will be converted to the same representation: since
these compare equal, this satisfies the comparison constraint, but it's worth knowing
this if you wish to use the encoding in some situation where this distinction matters.

Handling of NaN isn't (currently) guaranteed to be sensible.

sortable_unserialise SERIALISED_NUMBER
Convert a string encoded using sortable_serialise back to a floating point number.

This expects the input to be a string produced by sortable_serialise(). If the input
is not such a string, the value returned is undefined (but no error will be thrown).

The result of the conversion will be exactly the value which was supplied to
sortable_serialise() when making the string on platforms which represent doubles with
the precisions specified by IEEE_754, but may be a different (nearby) value on other
platforms.

TODO

       Error Handling
           Error handling for all methods liable to generate them.

       Documentation
           Add POD documentation for all classes, where possible just adapted from Xapian docs.

       Unwrapped classes
           The following Xapian classes are not yet wrapped: ErrorHandler, standard ExpandDecider
           subclasses (user-defined ones works), user-defined weight classes.

       Unwrapped methods
           The following methods are not yet wrapped: Enquire::get_eset(...) with more than two
           arguments, Query ctor optional "parameter" parameter, Remote::open(...), static
           Stem::get_available_languages().

           We wrap MSet::swap() and MSet::operator[](), but not ESet::swap(), ESet::operator[]().
           Is swap actually useful?  Should we instead tie MSet and ESet to allow them to just be
           used as lists?

CREDITS

       Thanks to Tye McQueen <tye@metronet.com> for explaining the finer points of how best to
       write XS frontends to C++ libraries, James Aylett <james@tartarus.org> for clarifying the
       less obvious aspects of the Xapian API, Tim Brody for patches wrapping ::QueryParser and
       ::Stopper and especially Olly Betts <olly@survex.com> for contributing advice, bugfixes,
       and wrapper code for the more obscure classes.

AUTHOR

       Alex Bowley <kilinrax@cpan.org>

       Please report any bugs/suggestions to <xapian-discuss@lists.xapian.org> or use the Xapian
       bug tracker <https://xapian.org/bugs>.  Please do NOT use the CPAN bug tracker or mail any
       of the authors individually.

LICENSE

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.