Provided by: libtree-rb-perl_0.500006-1_all 
NAME
Tree::RB - Perl implementation of the Red/Black tree, a type of balanced binary search
tree.
SYNOPSIS
use Tree::RB;
my $tree = Tree::RB->new;
$tree->put('France' => 'Paris');
$tree->put('England' => 'London');
$tree->put('Hungary' => 'Budapest');
$tree->put('Ireland' => 'Dublin');
$tree->put('Egypt' => 'Cairo');
$tree->put('Germany' => 'Berlin');
$tree->put('Alaska' => 'Anchorage'); # D'oh! Alaska isn't a Country
$tree->delete('Alaska');
print scalar $tree->get('Ireland'); # 'Dublin'
print $tree->size; # 6
print $tree->min->key; # 'Egypt'
print $tree->max->key; # 'Ireland'
print $tree->nth(0)->key; # 'Egypt'
print $tree->nth(-1)->key; # 'Ireland'
# print items, ordered by key
my $it = $tree->iter;
while(my $node = $it->next) {
printf "key = %s, value = %s\n", $node->key, $node->val;
}
# print items in reverse order
$it = $tree->rev_iter;
while(my $node = $it->next) {
printf "key = %s, value = %s\n", $node->key, $node->val;
}
# Hash interface
tie my %capital, 'Tree::RB';
# or do this to store items in descending order
tie my %capital, 'Tree::RB', sub { $_[1] cmp $_[0] };
$capital{'France'} = 'Paris';
$capital{'England'} = 'London';
$capital{'Hungary'} = 'Budapest';
$capital{'Ireland'} = 'Dublin';
$capital{'Egypt'} = 'Cairo';
$capital{'Germany'} = 'Berlin';
# print items in order
while(my ($key, $val) = each %capital) {
printf "key = $key, value = $val\n";
}
DESCRIPTION
This is a Perl implementation of the Red/Black tree, a type of balanced binary search
tree.
A tied hash interface is also provided to allow ordered hashes to be used.
See the Wikipedia article at <http://en.wikipedia.org/wiki/Red-black_tree> for further
information about Red/Black trees.
INTERFACE
new([CODEREF])
Creates and returns a new tree. If a reference to a subroutine is passed to new(), the
subroutine will be used to override the tree's default lexical ordering and provide a user
a defined ordering.
This subroutine should be just like a comparator subroutine used with sort, except that it
doesn't do the $a, $b trick.
For example, to get a case insensitive ordering
my $tree = Tree::RB->new(sub { lc $_[0] cmp lc $_[1]});
$tree->put('Wall' => 'Larry');
$tree->put('Smith' => 'Agent');
$tree->put('mouse' => 'micky');
$tree->put('duck' => 'donald');
my $it = $tree->iter;
while(my $node = $it->next) {
printf "key = %s, value = %s\n", $node->key, $node->val;
}
resort(CODEREF)
Changes the ordering of nodes within the tree. The new ordering is specified by a
comparator subroutine which must be passed to resort().
See "new" for further information about the comparator.
size()
Returns the number of nodes in the tree.
root()
Returns the root node of the tree. This will either be undef if no nodes have been added
to the tree, or a Tree::RB::Node object. See the Tree::RB::Node manual page for details
on the Node object.
min()
Returns the node with the minimal key.
max()
Returns the node with the maximal key.
nth(INDEX)
Returns the node at the given (zero based) index, or undef if there is no node at that
index. Negative indexes can be used, with -1 indicating the last node, -2 the penultimate
node and so on.
lookup(KEY, [MODE])
When called in scalar context, lookup(KEY) returns the value associated with KEY.
When called in list context, lookup(KEY) returns a list whose first element is the value
associated with KEY, and whose second element is the node containing the key/value.
An optional MODE parameter can be passed to lookup() to influence which key is returned.
The values of MODE are constants that are exported on demand by Tree::RB
use Tree::RB qw[LUEQUAL LUGTEQ LULTEQ LUGREAT LULESS LUNEXT LUPREV];
LUEQUAL
This is the default mode. Returns the node exactly matching the key, or "undef" if not
found.
LUGTEQ
Returns the node exactly matching the specified key, if this is not found then the
next node that is greater than the specified key is returned.
LULTEQ
Returns the node exactly matching the specified key, if this is not found then the
next node that is less than the specified key is returned.
LUGREAT
Returns the node that is just greater than the specified key - not equal to. This
mode is similar to LUNEXT except that the specified key need not exist in the tree.
LULESS
Returns the node that is just less than the specified key - not equal to. This mode
is similar to LUPREV except that the specified key need not exist in the tree.
LUNEXT
Looks for the key specified, if not found returns "undef". If the node is found
returns the next node that is greater than the one found (or "undef" if there is no
next node).
This can be used to step through the tree in order.
LUPREV
Looks for the key specified, if not found returns "undef". If the node is found
returns the previous node that is less than the one found (or "undef" if there is no
previous node).
This can be used to step through the tree in reverse order.
get(KEY)
get() is an alias for lookup().
iter([KEY])
Returns an iterator object that can be used to traverse the tree in order.
The iterator object supports a 'next' method that returns the next node in the tree or
undef if all of the nodes have been visited.
See the synopsis for an example.
If a key is supplied, the iterator returned will traverse the tree in order starting from
the node with key greater than or equal to the specified key.
$it = $tree->iter('France');
my $node = $it->next;
print $node->key; # -> 'France'
rev_iter([KEY])
Returns an iterator object that can be used to traverse the tree in reverse order.
If a key is supplied, the iterator returned will traverse the tree in order starting from
the node with key less than or equal to the specified key.
$it = $tree->rev_iter('France');
my $node = $it->next;
print $node->key; # -> 'France'
$it = $tree->rev_iter('Finland');
my $node = $it->next;
print $node->key; # -> 'England'
hseek(KEY, [{-reverse => 1|0}])
For tied hashes, determines the next entry to be returned by each.
tie my %capital, 'Tree::RB';
$capital{'France'} = 'Paris';
$capital{'England'} = 'London';
$capital{'Hungary'} = 'Budapest';
$capital{'Ireland'} = 'Dublin';
$capital{'Egypt'} = 'Cairo';
$capital{'Germany'} = 'Berlin';
tied(%capital)->hseek('Germany');
($key, $val) = each %capital;
print "$key, $val"; # -> Germany, Berlin
The direction of iteration can be reversed by passing a hashref with key '-reverse' and
value 1 to hseek after or instead of KEY, e.g. to iterate over the hash in reverse order:
tied(%capital)->hseek({-reverse => 1});
$key = each %capital;
print $key; # -> Ireland
The following calls are equivalent
tied(%capital)->hseek('Germany', {-reverse => 1});
tied(%capital)->hseek({-key => 'Germany', -reverse => 1});
put(KEY, VALUE)
Adds a new node to the tree.
The first argument is the key of the node, the second is its value.
If a node with that key already exists, its value is replaced with the given value and the
old value is returned. Otherwise, undef is returned.
delete(KEY)
If the tree has a node with the specified key, that node is deleted from the tree and
returned, otherwise "undef" is returned.
DEPENDENCIES
enum
INCOMPATIBILITIES
None reported.
BUGS AND LIMITATIONS
Please report any bugs or feature requests via the GitHub web interface at
<https://github.com/arunbear/perl5-red-black-tree/issues>.
AUTHOR
Arun Prasad "<arunbear@cpan.org>"
Some documentation has been borrowed from Benjamin Holzman's Tree::RedBlack and Damian
Ivereigh's libredblack (<http://libredblack.sourceforge.net/>).
ACKNOWLEDGEMENTS
Thanks for bug reports go to Anton Petrusevich, Wes Thompson, Petre Mierlutiu, Tomer
Vromen, Christopher Gurnee and Ole Bjorn Hessen.
LICENCE AND COPYRIGHT
Copyright (c) 2007, Arun Prasad "<arunbear@cpan.org>". All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same
terms as Perl itself. See perlartistic.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE,
TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
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ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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