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From Jorg Heymans>
Subject Re: accessing the pipeline structure
Date Fri, 10 Sep 2004 21:10:54 GMT

Stefano Mazzocchi wrote:


> This smells awefully close to "dynamic pipelines" which is something 
> that is considered an anti-pattern in cocoon (because it has been tried 
> in the 1.x generation and miserably failed).
> People see the pipeline machinery and think they can do things like SOAP 
> validation with it... well, it's not designed for that.
well that's what happens when people find a shiny new hammer - all they 
see are nails :)

> A while ago there was the proposal of "content-aware selectors" that 
> would allow you to implement what these guys want, I know that there is 
> also an implementation floating around even if we never reached 
> consensus on whether or not that was a good thing to have.
> What you are proposing is "context-dependent behavior"... well, this is 
well it's context-dependent behavior yes - but implemented in a context 
independent way.

> *exactly* what we are trying to avoid with pipelines: reusability of the 
> component is focused to be completely independent of the place where it 
> is used in the pipeline. Make the component "location dependent" and 
> kiss goodbye to orthogonality, and pretty soon you need a language that 
wasn't the guy trying to achieve the opposite? He wanted to be develop a 
component that he could plug anywhere because it autonomously finds out 
about the pipeline structure it's embedded in. Is that then "location" 
dependent because it needs to find out about it's location or "location 
independent" because it finds out about it's location and acts 
automagically. I'm confused now.

> indicates the potential 'neightbours' of each component... and maybe 
> people would want to add conditionals to that language... and pretty 
> soon people will ask you to deparate the cross-cutting pipeline concerns 
> into pipeline interceptors... and so on.
i see your point though here.


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