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Date: Wed, 16 May 2012 15:19:21 +0200
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Subject: Re: Hierarchical comments Hacker News style
From: Luca Matteis <lmatteis@gmail.com>
To: dev@couchdb.apache.org
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Ok. Where would it be appropriate to build such a tree? Can I do it in
a list function?
I'm using Couch directly and not interacting with it using other
languages, so I need Couch to do all the work.

On Wed, May 16, 2012 at 3:14 PM, Dirkjan Ochtman <dirkjan@ochtman.nl> wrote=
:
> On Wed, May 16, 2012 at 2:53 PM, Luca Matteis <lmatteis@gmail.com> wrote:
>> Isn't there a better way?
>
> Since the ordering of descendants depends on the scores of ancestors
> (if you're talking about getting the whole thread in order), and you
> don't want to update descendants when ancestors get modified (scores),
> there by definition is no way to cleanly do this. I think the best way
> you can do it is to emit the [ancestor_id, score] for each comment,
> which I think would allow you to build the tree structure in a single
> loop over all documents:
>
> docs, roots =3D {}, []
> for key, doc in documents:
> =A0 =A0if key[0] =3D=3D null:
> =A0 =A0 =A0 =A0 roots.append(doc.id)
> =A0 =A0docs[doc.id] =3D doc
> =A0 =A0if key[0]:
> =A0 =A0 =A0 =A0 docs[key[0]].children.append(doc.id)
>
> (In horrible pseudo-Python-JS.)
>
> Cheers,
>
> Dirkjan