SYNOPSIS

# Query is an abstract base class.
package MyQuery;
use base qw( Lucy::Search::Query );

sub make_compiler {
my ( $self, %args ) = @_;
my $subordinate = delete $args{subordinate};
my $compiler = MyCompiler->new( %args, parent => $self );
$compiler->normalize unless $subordinate;
return $compiler;
}

package MyCompiler;
use base ( Lucy::Search::Compiler );
...

DESCRIPTION

Query objects are simple containers which contain the minimum information necessary to define a search query.

The most common way to generate Query objects is to feed a search string such as 'foo AND bar' to a QueryParser's parse() method, which outputs an abstract syntax tree built up from various Query subclasses such as ANDQuery and TermQuery. However, it is also possible to use custom Query objects to build a search specification which cannot be easily represented using a search string.

Subclasses of Query must implement make_compiler(), which is the first step in compiling a Query down to a Matcher which can actually match and score documents.

CONSTRUCTORS

new( [labeled params] )

    my $query = MyQuery->SUPER::new(
        boost => 2.5,
    );

Abstract constructor.

• boost - A scoring multiplier, affecting the Query's relative contribution to each document's score. Typically defaults to 1.0, but subclasses which do not contribute to document scores such as NOTQuery and MatchAllQuery default to 0.0 instead.

ABSTRACT METHODS

make_compiler( [labeled params] )

Abstract factory method returning a Compiler derived from this Query.

• searcher - A Searcher.
• boost - A scoring multiplier. Defaults to the Query's own boost.
• subordinate - Indicates whether the Query is a subquery (as opposed to a top-level query). If false, the implementation must invoke normalize() on the newly minted Compiler object before returning it.

METHODS

set_boost(boost)

Set the Query's boost.

get_boost()

Get the Query's boost.

INHERITANCE

Lucy::Search::Query isa Lucy::Object::Obj.