NAME

TM::FAQ - Topic Maps, Frequently Angering Quirks

FAQ, TIPS AND PITFALLS

• Q: How can I get rid of these annoying topics occurrence, name, etc. which I have not put into the map in the first place, but which are in there in all cases?

  A: These infrastructure topics are needed to make the map complete (everything used is defined). If you want to filter these out, you can get them first via

      my @infra = $tm->mids (keys %{$TM::PSI::topicmaps->{mid2iid}})

  To deduct them from the list of all topics

      my @all = $tm->midlets;

  You can do:

      # make lookup for speed
      my %infra;
      @infra{ @infra } = (1) x @infra;
  
      my @non_infra = grep (!$infra{$_}
                         && !$tm->retrieve ($_),
                      $tm->midlets);

  The retrieve looks up whether the topic is an assertion. Most likely, you would not want these as well then.

• Q: How can I get all names and/or occurrences of a topic?

  A: If you have a topic identifier mytopic in your hand, then you can get all characteristics (= names and occurrences, but not associations) with

      my @cs = $tm->match_forall (char => 1, irole => $tm->mids ('mytopic'));

  Then you can filter occording the type, the scope, the data type value or the KIND. The latter tells you whether an assertion is a name or occurrence. For example those occurrences which are occurrences and not anything specials as, say, homepage:

      my @occs  = map { $_->[0] } map { TM::get_x_players ($tm, $_, 'tm://value') } grep ($_->[TM->TYPE] eq 'tm://occurrence', @cs);

• Q: How do these get_x_role functions work? What does does not honor subclassing mean?

  A: @@@@@@@@@@@@@

  (is-father-of) father: godzilla child: kidzilla

  father subclasses parent

  dann kriegst du mit

    get_x_role ($tm, $a, '...father')     =======> godzilla
    get_x_role ($tm, $a, '...parent')     =======> nix
    get_role   ($tm, $a, '...parent')     =======> godzilla

• Timestamps of resources

  @@@ files have UNIX time resolution (second), TM uses HiRes::Time @@@@

COPYRIGHT AND LICENSE

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.