[Zope3-dev] Re: Better access to APIs in paths (was Re: needing views clues - template/title troubles)

[Evan Simpson]

Jim Fulton wrote:
>   context/dc:title
> 
> which looks up the title api in the dc namespace for the object given
> by the context.
[...]
> In Python code, we could do:
> 
>   api(context).dc.title

Why do you prefer this?  I find it much easier to think in terms of 
accessing the 'title' property/attribute/whatever after applying the 
'dc' adapter.

>    <api namespace="zope" name="title"
>      for="zope.app.interfaces.annotation.IAnnotatable"
>      factory="zope.app.dublincore.annotatableadapter.TitleAPI">
>        title meta-data attribute
> 
>        The title API attribute provides access to the (unqualified)
>        Dublin-Core "Title" meta-data element.
>    </api>

Ack! We have to implement and declare a separate API for every single 
meta-data attribute??

> Some people have suggested that namespaces are just adapters.
> I think that this would be a bad idea as it would lead to very many
> small namespaces.

Only if there are a plethora of small APIs.  In the example above, I 
assumed that 'dc' is an adapter from IAnnotatable to an interface 
(IAnnotationAccess?) that provides access to *all* of the Dublin Core 
meta-data elements.

> User's objected stenuously to including xml namespace declarations in
> their zpts. We eventually, removed the necessity for declaring namespaces
> in HTML zpts. I don't think requiring namspace declarations for API
> functions would be popular.

Part of the objection, I suspect, was that declaring TAL and METAL 
namespaces was utter boilerplate.  At least in HTML templates, no one 
cared about the ability to choose their own prefix, and the chances of a 
prefix clash were essentially nil.  In XML namespace declarations are 
quite common.

I imagine that allowing configurable pre-defined prefixes for undeclared 
namespaces would be a good thing, especially for namespaces like the 
Dublin Core that are built into Zope and widely used.  Cutting down the 
verbosity of the declaration would help, as well:

   tal:namespaces="dc zope:DublinCore"

I'm not sure what value conflation with XML namespaces adds, given the 
configurability of Zope 3. Under my interpretation of the API 
functionality, it would make sense to write:

   tal:adapters="dc zope.DublinCore"

...where the name 'zope' lives in the root namespace for registered 
adapters.

> Also note that this new syntax will be used in TALES outside of zpt.
> For example, it would be useful to use these in simple stand-alone
> TALES expressions where namespace declarations are inconventient or
> impossible

This would be another good argument for default prefixes.  Also, we 
could allow expressions such as "object/zope.DublinCore:title" and 
"widget/plone.FooBar:baz", i.e. the prefix can be the full name of the 
adapter.

Cheers,

Evan @ 4-am