Re: [RT] since we are at it, more irons in the template fire: Xenon

From: Peter Hunsberger <>
Date: Wed, 8 Dec 2004 14:26:45 -0600

On Wed, 08 Dec 2004 12:10:09 -0500, Stefano Mazzocchi
<> wrote:

> Now, let me tell you a story about templates.

As the sound of the theme music from Beverly Hillbillies rises in the


> I like the name (and the concept) of lenses.
> We have identified the need to have "isolated and reusable programmatic
> artifacts that know how to transform something into SAX events". They
> were named 'taglib' because the syntax normally used to identify them is
> a namespaced element (a 'tag').
> The problem with the name is that it has been used (and abused!) in too
> many systems and brings memories of abuse and FS. Like the infamous <if>
> tag (also abused by XSLT)
> I think we should call our CTemplates taglibs "lenses" instead.

For our internal templating system we're currently implementing a
concept we call "filters" that lets one declaratively define
conditional portions of a template/view. As I read your story (:-) I
kept thinking that lenses and filters lined up pretty much the same.
Then I jumped over to the Xenon description and found a "xe:filter" as
part of the lens description. I won't have time to dissect everything
completely, but semantically a lens as used in Xenon seems to be a
filter (and filters as used in Xenon seem to be conditionals). If so,
I think the idea makes perfect sense, at least for our system

However, I'm not quite sure that the lens concept maps exactly to
everything that is being discussed WRT Cocoon? In particular, there
seems to be more of a active modifier role (ie "turn something into
SAX events") to what people are looking for for Cocoon? Then again,
maybe that's part of the problem and why you like the name "lens"?

I'll also note that if you take the optical analogy literally, you
want both lenses and filters working together as separate components
and not mixed together the way Xenon seems to do. I wonder if there's
some SOC in the view model that really remains to be completely
abstracted? I'm not sure "lens" is an abstraction I find completely

Peter Hunsberger
Received on Wed Dec 08 2004 - 20:26:40 EST

This archive was generated by hypermail 2.3.0 : Thu Aug 09 2012 - 16:39:17 EDT