NAME

       Tree::RedBlack::Node - Node class for Perl implementation of Red/Black tree

SYNOPSIS

       use Tree::RedBlack; my $t = new Tree::RedBlack; $t->insert(3, 'dog'); my $node = $t->node(3); $animal =
       $node->val;

DESCRIPTION

       A Tree::RedBlack::Node object supports the following methods:

       key ()
           Key of the node.  This is what the nodes are sorted by in the tree.

       val ($)
           Value  of the node.  Can be any perl scalar, so it could be a hash-ref, f'rinstance.  This can be set
           directly.

       color ()
           Color of the node.  1 for "red", 0 or undef for "black".

       parent ()
           Parent node of this one.  Returns undef for root node.

       left ()
           Left child node of this one.  Returns undef for leaf nodes.

       right ()
           Right child node of this one.  Returns undef for leaf nodes.

       min ()
           Returns the node with the minimal key starting from this node.

       max ()
           Returns the node with the maximal key starting from this node.

       successor ()
           Returns the node with the smallest key larger than this node's key, or this node if it  is  the  node
           with the maximal key.

       predecessor ()
           Similar to successor. WARNING: NOT YET IMPLEMENTED!!

       You can use these methods to write utility routines for actions on red/black trees.  For instance, here's
       a  routine  which writes a tree out to disk, putting the byte offsets of the left and right child records
       in the record for each node.

           sub dump {
             my($node, $fh) = @_;
             my($left, $right);
             my $pos = tell $fh;
             print $fh $node->color ? 'R' : 'B';
             seek($fh, 8, 1);
             print $fh $node->val;
             if ($node->left) {
               $left = dump($node->left,$fh);
             }
             if ($node->right) {
               $right = dump($node->right,$fh);
             }
             my $end = tell $fh;
             seek($fh, $pos+1, 0);
             print $fh pack('NN', $left, $right);
             seek($fh, $end, 0);
             $pos;
           }

       You would call it like this:

           my $t = new Tree::RedBlack;
           ...
           open(FILE, ">tree.dump");
           dump($t->root,\*FILE);
           close FILE;

       As another example, here's a simple routine to print a human-readable dump of the tree:

           sub pretty_print {
             my($node, $fh, $lvl) = @_;
             if ($node->right) {
               pretty_print($node->right, $fh, $lvl+1);
             }
             print $fh ' 'x($lvl*3),'[', $node->color ? 'R' : 'B', ']', $node->key, "\n";
             if ($node->left) {
               pretty_print($this->left, $fh, $lvl+1);
             }
           }

       A cleaner way of doing this kind of thing is probably to allow sub-classing of Tree::RedBlack::Node,  and
       then allow the Tree::RedBlack constructor to take an argument saying what class of node it should be made
       up out of. Hmmm...

AUTHOR

       Benjamin Holzman <bholzman@earthlink.net>

SEE ALSO

       Tree::RedBlack

perl v5.36.0                                       2022-10-22                                          Node(3pm)