But maybe you can do something like this in your start_element():

    if ($all_done) {
      $self->end_document();
      die "Ended early!\n";
    }
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Then in your parsing code you can catch the exception with eval and handle it:

    eval { # parse call here };
    if ($@ and $@ =~ /Ended early/) {
      # it's ok
    } elsif ($@) {
      die $@;
    }
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For a slightly prettier solution, create a new exception class based on XML::SAX::Exception and key on that class rather than the message in $@.

-sam