Question

The variable META{"parent" ...} (VarMETA) will generate those nifty breadcrumbs to lead you recursively back up through the parentage.

I need to do that, but instead of the $topic name, I need to use a formfield value from that topic.

I need this because I"m using AUTOINCxxx style topics. Having

 Top > Folder001 > Folder002 

Top > Human Resources > Department of Firing People

I've played around with using the FormattedSearch arguments (all those nifty ones that start with $) within a format argument to META-parent but whatever set that supports, it doesn't include $formfield.

Environment

-- MatthewKoundakjian - 02 Jul 2007

Answer

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I'm investigating AddFormfieldParamToMetaParent as kind of what I was on about... it's a patch to some past version, but it looks like I can make it work. Was hoping for a high-level solution, but a solution is better than none.

-- MatthewKoundakjian - 08 Jul 2007

This is currently not possible. You'd need a TopicDisplayName feature, whgich is porposed but will not be implemented in the upcoming TWiki 4.2 release.

You could try nested searches, but this assumes fixed number of nesting, such as 3 levels. And nested searches are slow.

An alternative is to enhahance META{"parent" ...} to allow arbitrary display of each parent link.

-- PeterThoeny - 08 Jul 2007

Upon brief examination, the TopicDisplayName feature looks like a good approach.

I'm going to poke around in renderParent to see if I can coherently enhance META{"parent"} ...

Thanks.

-- MatthewKoundakjian - 09 Jul 2007

Ok, I got what I wanted done. I had to hack on renderParent in Render.pm and I made a duplicate function to getTopicParent in Store.pm, which I called getTopicField.

getTopicField differs by getTopicParent on the lines with " #####" on them.

hal 163# diff -nbi twiki-4.1.2-orig/lib/TWiki/Store.pm twiki-4.1.2/lib/TWiki/Store.pm
a1448 43
---++ ObjectMethod getTopicField (  $web, $topic, $fieldname  ) -> $string

Get the value of the topic's named fields. Needs to be fast because
of use by Render.pm.

=cut

# SMELL: does not honour access controls

sub getTopicField {  #####
    my( $this, $web, $topic, $fieldname ) = @_;   #####
    ASSERT($this->isa('TWiki::Store')) if DEBUG;
    ASSERT(defined($web)) if DEBUG;
    ASSERT(defined($topic)) if DEBUG;

    return undef unless $this->topicExists( $web, $topic );

    my $handler = $this->_getHandler( $web, $topic );

    my $strm = $handler->getStream();
    my $data = '';
    while( ( my $line = <$strm> ) ) {
        if( $line !~ /^%META:/ ) {
            next;   #####
        } else {
            $data .= $line;
        }
    }
    close( $strm );

    my $meta = new TWiki::Meta( $this->{session}, $web, $topic );
    $this->extractMetaData( $meta, \$data );
    my $parentMeta = $meta->get( 'FIELD', $fieldname );   #####
    return $parentMeta->{value} if $parentMeta;   #####
    return undef;
}

=pod

For changes to renderParent, I am just putting in a diff...

hal 167# diff -nbi twiki-4.1.2-orig/lib/TWiki/Render.pm twiki-4.1.2/lib/TWiki/Render.pm
d124 1
a124 6
    my $formfield =   $ah->{formfield} || '';
        my $format;
    if ($formfield) {
          if ($ah->{format}) { $format = $ah->{format};}
          else               { $format = '[[$web.$topic][$formfield]]';}  }
        else { $format =      $ah->{format} || '[[$web.$topic][$topic]]'; }
a132 1
        my $pTopicFormName;
a145 2
        $pTopicFormName = 
                       $store->getTopicField( $pWeb, $pTopic, $formfield ) || $pTopic;
a150 1
        $text =~ s/\$formfield/$pTopicFormName/g;

I've not tested it exhaustively, but pretty much, it adds a field called "formfield" and allows that to be a part of the format statment (which now can have topic, web and formfield values).

I am now using:

%TMPL:DEF{"breadcrumb"}%%ICON{"arrowbright"}%%META{"parent" formfield="FolderSummary"}%%TMPL:END%

-- MatthewKoundakjian - 09 Jul 2007