[Bioperl-l] Subclassing Bio::Seq ? Extending Bio::Perl
JK (Jesper Agerbo Krogh)
JK at novozymes.com
Tue Oct 24 13:59:10 EDT 2006
> I think you've generally taken the right path, but see below.
> First off, object factories are used extensively already but not yet
> in each and every place where Bioperl creates an object internally.
> Achieving your goal may entail fixes to Bioperl to use a factory
> instead of a hard-coded module name. Also be on the lookout for
> factory() or seq_factory() methods for classes whose work entails
> creating sequence objects and that already give you control over the
> type to be created.
Can you elaborate/describe this a bit more?
> The problem that hits you here though isn't one of determining the
> type of the object to be created, because the respective method
> doesn't create a sequence object. It only returns the sequence object
> that the feature has a reference to.
This was what Data::Dumper told me, but stuff I'd likewise would like to
change was to get a RichSeq object returned every-time from Bio::Seq, adding
in the stuff that allways seems appropriate.
> The reason that this is a Bio::PrimarySeq and not a Bio::Seq or your
> extension of the latter is that the Perl garbage collector can't deal
> with circular references.
Doesn't Scalar::Util::weaken solve that?
> Having said all that, note that if all what you want to do is
> defining computations on Bio::Seq objects, as opposed to storing
> values for additional attributes, the best design approach is not to
> extend the class but to create a class with those computations as
> static methods (which would accept the seq object on which to compute
> as an argument; e.g., print $seqComputations->message_digest($seq)).
I could but there are some functionality that I'd by design would like to
have available on every sequence in the system. This way I would end up
coding the functionality for getting the message_digest every place that
I needed to get the value (which would be quite often in this application),
whereas it by design belongs into the Bio::Seq-stuff.
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