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From Nicola Ken Barozzi <>
Subject Re: Link view goodness (Re: residuals of MIME type bug ?)
Date Sun, 29 Jun 2003 09:34:01 GMT

Jeff Turner wrote, On 29/06/2003 8.03:
> I still have the feeling that a link-gatherer transformer is mixing
> concerns a bit, and that two-pass is conceptually nicer:
> - We're abusing the name 'transformer', since nothing is transformed.
>   If we're really going to go this way, let's define a new sitemap
>   element, <map:link-gatherer/>.

There are transformers that do not transform, it's not unusual, 
although, since the sitemap has a new contract on links (see at the 
bottom), it might make sense.

> - Link gathering is irrelevant for online situations, so we pay some
>   performance penalty having a link-gatherer transformer.  This
>   illustrates why I think it mixes concerns.


> - It's easy to forget to define a link-gatherer transformer for new
>   pipelines.  Link-view is cross-cutting and doesn't have this
>   problem.

Again, exactly.

> I'm not very familiar with the code; is there some cost in keeping the
> two-pass CLI alive, in the faint hope that caching comes to its rescue
> one day?

Actually it was three-pass.

>>Thanks for engaging with me on this - I appreciate it.
> Thank _you_; an improved CLI will make Forrest significantly more
> usable.

For your pleasure, and of interested parties, the previous threads:

And a couple of mails:

The last mail in particular explains the current new-CLI method:

So basically we are adding a contract to the sitemap, by saying that
each sitemap implementation has to provide a list of links if requested
to (as seen above).

As you state, a Transformer does not feel right. In fact, a sitemap has 
now a new contract that it has to give links. The question is: how can 
it be made more versatile? Who can we tell the pipeline where we want 
the link gathering to occur?

What about a named pipeline that is inserted by the link gatherer where 
it gets the links? What about using a spacial label to indicate where to 
gather links?

Just food for thought.

Nicola Ken Barozzi         
             - verba volant, scripta manent -
    (discussions get forgotten, just code remains)

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