NAME¶
CQL::Visitor - visit nodes in a CQL parse tree
SYNOPSIS¶
package MyVisitor;
use base qw( CQL::Visitor );
sub term {
my ($self,$node) = @_;
# do something to the node
}
# later on
my $parser = CQL::Parser->new();
my $root = $parser->parse($cql);
my $visitor = MyVisitor->new();
$vistor->visit($root);
DESCRIPTION¶
CQL::Visitor provides a simple interface for visiting nodes in your parse tree.
It could be useful if you want to do something like change a query like this:
dc.title=foo and dc.creator=bar
into
title=foo and creator=bar
Or some similar procedure. You simply create a new subclass of CQL::Visitor and
override the appropriate method, such as
term(). Every term that is
encountered during the traversal will be handed off to your
term()
method.
Note: at the moment only
term() is supported because that's what was
needed, but if you need other ones feel free to add them, or ask for them.
METHODS¶
new()¶
visit()¶
Call this to traverse your parse tree, starting at the root.
term()¶
Your subclass should override this, and do something meaningful with the
CQL::TermNode object.