NAME

TPath::Index - tree-specific database

VERSION

version 1.007

SYNOPSIS

  my $f = MyForester->new;      # hypothetical forester for my sort of tree
  my $root = next_tree();       # generate my sort of tree
  my $index = $f->index($root); # construct reusable index for $root

DESCRIPTION

A cache of information about a particular tree. Reuse indices to save effort.

The chief function of an index is to enable an expression to map a node to its ancestors for those trees that provide this mapping themselves. All tree-specific caches belong here, though.

You should regard the methods and attributes of a TPath::Index as private. The public function of an index is to be the optional second argument of a TPath::Expression's select method.

ATTRIBUTES

indexed

The map from ids to nodes.

root

The root of the indexed tree.

METHODS

is_root

Expects a node. Returns whether this node is the root of the tree indexed by this index.

index

Cause this index to walk its tree and perform all necessary indexation.

parent

Expects a node and returns the parent of this node.

pc_index

Record the link from child to parent. If this index is unnecessary for a particular variety of tree -- nodes know their parents -- then you should override this method to be a no-op. It assumes all nodes are references and will throw an error if this is not the case.

id

Returns the unique identifier, if any, that identifies this node. This method delegates to the forester's id method.

The TPath::Forester that generated this index.

AUTHOR

David F. Houghton <dfhoughton@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by David F. Houghton.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

cpanm TPath

perl -MCPAN -e shell
install TPath