XTM::topic(3pm)

XTM::topic - Topic Map management, Topic

  use XTM::topic;

  my $t = new XTM::topic;
  ...
  print join (",", @{$t->occurrences()});
  print "bliss and happiness" if $t->has_instanceOf ('t-billionair');

  # now this time I am providing the id myself
  my $t2 = new XTM::topic (id => '1234');

  # there is also a cheap way to populate the topic with a default
  my $t3 = new XTM::topic (id => '1234', populate => \&XTM::topic::default_populate);

  # see XTM::generic for more methods

This package provides the primitive class Topic for Topic Maps.
Constructor The constructor expects a hash with following (optional) fields: a topic id (unique in the map in use), if not given, it will be generated a code reference to a subroutine populating the topic. There are the following predefined subroutines: This routine expects as first parameter a "XTM::topic"-blessed object and fills in the PSI topic as 'instanceOf', global scope where appropriate. It also generates in a fairly ad-hoc manner a 'baseName' from the topic id (substituting '-' by ' ').

  $t = new XTM::topic ('id' => 'x123');

Methods Following accessor methods are available via XTM::generic (see that package how to set/add values): @{ $t->baseNames}

returns list reference of XTM::baseName nodes. @{ $t->instanceOfs}

returns list reference of XTM::instanceOf nodes. $t->subjectIdentity

returns a XTM::subjectIdentity node Other methods are: print $t->id

$t->id ("x123");

returns the id of the topic. If provided with a non-empty scalar parameter, this value will be used to change the id. @{ $t->occurrences }

$t->occurrences ( $coderef )

$t->occurrences ( $arrayref )

returns the occurrences of the topic as a list reference. If provided with a CODEREF parameter, this subroutine will be used to filter the occurrences. If provided with a ARRAYREF parameter, this will be used as new value. $t->map

$t->map ( $newmap )

is an accessor method for the "map" component. $t->has_instanceOf ( $type_topic_id )

returns true if the topic is a direct subtype of a topic specified as "tid" for the only parameter.

Example:

   print "bliss and happiness" if $t->has_instanceOf ('t-billionair');

$t->add_defaults

This methods add default values according to the XTM standard. Specifically, it assures that $t->canonicalize

This method simplifies the topic by eliminating duplicates as prescribed in F.6. @{ $t->connected }

returns a list reference of all topic references mentioned in this topic. These references might be 'internal' or 'external' ones.

Example:

   foreach (@{$t->connected}) {
     print "$t->id mentions $_\n";
   }

$t->xml ( $xmlwriter )

returns an XML representation of the topic.

Example:
$xmlwriter = new XML::Writer ...
...
$t->xml($xmlwriter); # outputs all onto $xmlwriter XTM, XTM::generic Copyright 200[1-2], Robert Barta <[email protected]>, All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. http://www.perl.com/perl/misc/Artistic.html