[Zope3-Users] Re: zalchemy integration

Jeff Shell eucci.group at gmail.com
Mon Aug 14 15:00:19 EDT 2006

On 8/14/06, Stephan Richter <srichter at cosmos.phy.tufts.edu> wrote:
> Right, so you fixed the problem with the provider TALES expression,
> which has to do update()/render() at the same time. My question
> is: How do you know which content providers are used by a view? Do you
> manually list them?

A Page class (or any provider manager) may optionally list names. The
names also provide some ordering support (ensuring that provider A is
updated before provider B). If no names are listed in the class, then
all Content Providers registered for the page are looked up::

      self._content_providers = dict(zapi.getAdapters(
          (self.context, self.request, self), IContentProvider

> I was thinking about implementing a way to inspect TAL code to determine all
> the providers that should be looked up before rendering. I even talked to
> Fred about it already; but it is non-trivial, if I understand him correctly.

I wouldn't want to be bound to TAL though. As I mentioned, we use a
STAN-inspired system for generating HTML in many places where there's
no desire to maintain a separate file just to render something simple
- or even moderately complex.

As we've also started implementing a system inspired by Rails Helpers
which eases some generation of common tasks from formatting to
link/URL generation, our need to TAL has decreased. It's still useful
in design heavy sites, but I'm really starting to wish for some
simplified expressions (even TALES expressions would be nice) to do
structured inserts with a helluva-lot-less typing.

We still use page templates fairly heavily. I just wouldn't want to
depend on TAL code so heavily that any other template/html/xml
generation system one wants to plug in really becomes a second or
third class citizen at that point.

> Right, I see you use viewlets/providers heavily; at least we are not
> the only ones. :-) I would be interested in a lot more dialog here to
> share best practices and code.

We haven't gone into super-heavy usage, but that should start changing
this week as we push for the front end UI of this project. Then we'll
see if my theories worked :).

> BTW, another part of the UI power tools is zc.table. I will publish a
> bunch of extensions later this week.

I haven't had too much time to look at `zc.table`. It was a little
overwhelming last time I looked at it... I think because of the
'resource library' system being kindof scary. While I haven't pushed
my full-Page system concept to its extremes yet, I'm hoping that it
can - perhaps - deal with the issues of 'A widget in some form on the
page wants to add some javascript or css to the head' issue without
badgering the response; something similar to Seaside's `updateRoot`

Jeff Shell

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