Re: zope.viewlet and zope.contentprovider - options for Zope 2 and Plone 3

On Sun, 09 Apr 2006 21:25:39 +0100, Martin Aspeli wrote:
> Now, I have a feeling that this could be faked in Zope 2 with something
> like:
> 
>       <tal:block replace="structure python:provider('provider.name')" />
> 
> the object 'provider' would have to be defined globally (in
> global_defines.pt in Plone). Its implementation would basically be
> identical to the TALESProviderExpression in zope.contentprovider, with a
> __call__() method that called update() and render() on an IContentProvider
> looked up by the name it was passed.
> 
> The tricky part is the ITALNamespaceData update magic that needs to read
> the TAL context:
> 
>   - Is there some way a python object referred in an expression like the
> one above could be passed or acquire (literally or figuratively) TAL
> objects defined in the current context at that point?

Precisely because I wanted to "emulate" something like viewlets, I have a
ready solution to do this kind of reentrance in Zope2,
see http://www.zope.org/Members/ree/zptcontext . It's a big time hack for
more reasons, mostly because the pagetemplate code is not designed
re-entrant. It works pretty stable, though, in practice. 

The usage is get the econtext from python via get_econtext, and then call
the page template in a reentrant way via pt_render_in_econtext. You can
also think about this as a way to substitute macros.

However having the real viewlets that work in Plone would be a greater
deal. Also the closer we get to Zope3 the more things we can reuse instead
of duplicating them, so that's a very strong reason for switching to the
Z3 template rendering engine asap.

-- 
Balazs Ree jabber + email: ree-DIAULbSzolw@xxxxxxxxxxxxxxxx
           ICQ: 75955071   AIM + skype: reebalazs




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