KinoSearch::Search::QuUseraContributed Perl KinoSearch::Search::QueryParser(3)NAMEKinoSearch::Search::QueryParser - Transform a string into a Query
object.
SYNOPSIS
my $query_parser = KinoSearch::Search::QueryParser->new(
schema => $searcher->get_schema,
fields => ['body'],
);
my $query = $query_parser->parse( $query_string );
my $hits = $searcher->hits( query => $query );
DESCRIPTION
QueryParser accepts search strings as input and produces
KinoSearch::Search::Query objects, suitable for feeding into
IndexSearcher and other Searcher subclasses.
The following syntactical constructs are recognized by QueryParser:
* Boolean operators 'AND', 'OR', and 'AND NOT'.
* Prepented +plus and -minus, indicating that the labeled entity
should be either required or forbidden -- be it a single word, a
phrase, or a parenthetical group.
* Logical groups, delimited by parentheses.
* Phrases, delimited by double quotes.
Additionally, the following syntax can be enabled via
set_heed_colons():
* Field-specific constructs, in the form of 'fieldname:termtext' or
'fieldname:(foo bar)'. (The field specified by 'fieldname:' will be
used instead of the QueryParser's default fields).
CONSTRUCTORS
new( [labeled params] )
my $query_parser = KinoSearch::Search::QueryParser->new(
schema => $searcher->get_schema, # required
analyzer => $analyzer, # overrides schema
fields => ['bodytext'], # default: indexed fields
default_boolop => 'AND', # default: 'OR'
);
Constructor.
· schema - A Schema.
· analyzer - An Analyzer. Ordinarily, the analyzers specified by
each field's definition will be used, but if "analyzer" is
supplied, it will override and be used for all fields. This can
lead to mismatches between what is in the index and what is being
searched for, so use caution.
· fields - The names of the fields which will be searched against.
Defaults to those fields which are defined as indexed in the
supplied Schema.
· default_boolop - Two possible values: 'AND' and 'OR'. The default
is 'OR', which means: return documents which match any of the query
terms. If you want only documents which match all of the query
terms, set this to 'AND'.
METHODSparse(query_string)
Build a Query object from the contents of a query string. At present,
implemented internally by calling tree(), expand(), and prune().
· query_string - The string to be parsed. May be undef.
Returns: a Query.
tree(query_string)
Parse the logical structure of a query string, building a tree
comprised of Query objects. Leaf nodes in the tree will most often be
LeafQuery objects but might be MatchAllQuery or NoMatchQuery objects as
well. Internal nodes will be objects which subclass PolyQuery:
ANDQuery, ORQuery, NOTQuery, and RequiredOptionalQuery.
The output of tree() is an intermediate form which must be passed
through expand() before being used to feed a search.
· query_string - The string to be parsed.
Returns: a Query.
expand(query)
Walk the hierarchy of a Query tree, descending through all PolyQuery
nodes and calling expand_leaf() on any LeafQuery nodes encountered.
· query - A Query object.
Returns: A Query -- usually the same one that was supplied after in-
place modification, but possibly another.
expand_leaf(query)
Convert a LeafQuery into either a TermQuery, a PhraseQuery, or an
ORQuery joining multiple TermQueries/PhraseQueries to accommodate
multiple fields. LeafQuery text will be passed through the relevant
Analyzer for each field. Quoted text will be transformed into
PhraseQuery objects. Unquoted text will be converted to either a
TermQuery or a PhraseQuery depending on how many tokens are generated.
· query - A Query. Only LeafQuery objects will be processed; others
will be passed through.
Returns: A Query.
prune(query)
Prevent certain Query structures from returning too many results.
Query objects built via tree() and expand() can generate "return the
world" result sets, such as in the case of "NOT
a_term_not_in_the_index"; prune() walks the hierarchy and eliminates
such branches.
'NOT foo' => [NOMATCH]
'foo OR NOT bar' => 'foo'
'foo OR (-bar AND -baz) => 'foo'
prune() also eliminates some double-negative constructs -- even though
such constructs may not actually return the world:
'foo AND -(-bar)' => 'foo'
In this example, safety is taking precedence over logical consistency.
If you want logical consistency instead, call tree() then expand(),
skipping prune().
· query - A Query.
Returns: a Query; in most cases, the supplied Query after in-place
modification.
set_heed_colons(heed_colons)
Enable/disable parsing of "fieldname:foo" constructs.
make_term_query( [labeled params] )
Factory method creating a TermQuery.
· field - Field name.
· term - Term text.
Returns: A Query.
make_phrase_query( [labeled params] )
Factory method creating a PhraseQuery.
· field - Field that the phrase must occur in.
· terms - Ordered array of terms that must match.
Returns: A Query.
make_and_query(children)
Factory method creating an ANDQuery.
· children - Array of child Queries.
Returns: A Query.
make_or_query(children)
Factory method creating an ORQuery.
· children - Array of child Queries.
Returns: A Query.
make_not_query(negated_query)
Factory method creating a NOTQuery.
· negated_query - Query to be inverted.
Returns: A Query.
make_req_opt_query( [labeled params] )
Factory method creating a RequiredOptionalQuery.
· required_query - Query must must match.
· optional_query - Query which should match.
Returns: A Query.
INHERITANCEKinoSearch::Search::QueryParser isa KinoSearch::Object::Obj.
COPYRIGHT AND LICENSE
Copyright 2005-2010 Marvin Humphrey
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.12011-06-20KinoSearch::Search::QueryParser(3)
