Ed Summers

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.