[Xapian-discuss] use TermGenerator to get the term

[Olly Betts]

On Thu, Oct 29, 2009 at 02:26:58PM -0500, Ying Liu wrote:
> I have a question about use the TermGenerator alone by Perl. Someone  
> asked this question before and his code is in C++.  
> (http://lists.xapian.org/pipermail/xapian-discuss/2008-November/006109.html). 
> My code is in Perl. Can I get the term by the position just by  
> TermGenerator?
>
>    my $analyzer = Search::Xapian::TermGenerator->new;
>    $analyzer->index_text("hello Xapian world");
>    my $curr_position = $analyzer->get_termpos();     
> $analyzer->set_termpos(2);     $curr_position = $analyzer->get_termpos();
>    $analyzer->increase_termpos(1);
>    $curr_position =  $analyzer->get_termpos();
>
> If I set the document and then use $doc to iterate the term list, terms  
> are order  alphabetically. I don't know how to use the positer().
>
> $analyzer->set_document($doc);
> my $termlist_begin = $doc->termlist_begin();
> $termlist_begin++;
> my $term = $termlist_begin->get_document();

Um, that line is wrong as TermIterator doesn't have a get_document()
method.  I think you mean:

    my $term = $termlist_begin->get_termname();

To iterator the positions for TermIterator $term_itor you'd do:

    my $pos_itor = $term_itor->positionlist_begin();
    while ($pos_itor ne $term_itor->positionlist_end()) {
	print $pos_itor->get_termpos(), "\n";
	++$pos_itor;
    }

> Btw, if I want to use ESet, how to assign the text, similar method like  
> index_text for ESet?

The ESet is generated from the same terms used for searching.

Cheers,
    Olly