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Robert Barta


TM::Tree - Topic Maps, trait for induced tree retrieval


  use TM::Materialized::AsTMa;
  my $tm = new TM::Materialized::AsTMa (file => 'old_testament.atm');
  Class::Trait->apply ( $tm => 'TM::Tree' );

  # old-testament pedigree
  print Dumper $tm->tree (lid   => 'adam',
                          type  => 'has-parent',
                          arole => 'parent',
                          brole => 'child' );

  # new-testament inverse pedigree
  print Dumper $tm->tree (lid   => 'gw-bush',
                          type  => 'has-parent',
                          arole => 'child',
                          brole => 'parent' );


Obviously, topic maps can carry information which is tree structured. A family pedigree is a typical example of it; associations having a particular type, particular roles and you can derive a tree structure from that.

This is exactly what this operator does: it takes one topic map basis and primed with a starting node, an association type and two roles a tree will be returned to the caller.




$treeref = $tm->tree ( $start_topic, $type_topic, $role_topic, $role_topic, [ depth => $integer ])

$treeref = $tm->tree_x ( $start_topic, $type_topic, $role_topic, $role_topic, [ depth => $integer ])

This function will analyze the topic map and will detect all maplets of the given type (direct and indirect ones) having the specified roles. Starting from the start topic it will so find other topics playing the brole. Those will be used as a next starting point, and so forth.

To avoid the tree to become too big, you can impose an optional limit. Loops are detected.

Every output tree node contains following fields:


the lid of the node


a list reference of child nodes, there is no specific sort order


Note: This is currently deactivated.

for convenience this list reference contains all children, grand-children, grand-grand children.... of this node (this list is neither sorted nor unique out of performance considerations).

The version tree_x does not honor subclassing of roles and type (but tree does). This means that is can be considerably faster, especially if you use it for taxonomy stuff with isa and is-subclass-of.


$treeref = $tm->taxonomy ([ $start_lid ])

This function is a specialization of tree, in that it looks at a particular association type (is-subclass-of) and the appropriate roles (superclass, subclass). Obviously the result is a tree holding all subtypes.

The only optional parameter is a toplet lid; that becomes the starting point of the tree. If that parameter is missing, thing is assumed.




Copyright 200[3-6] by Robert Barta, <drrho@cpan.org>

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