[Zope-dev] Re: Adapters in Zope 2

[Tres Seaver]

Santi Camps wrote:
>>>Casey Duncan wrote:
>>>
>>>>Zope2 folders are designed for this. They are really just "blank
>>>>objects" where you can specify your own methods in instance space.
>>>>Traditionally in Zope2, there are two ways to do this: by adding
>>>>"method" objects (External Methods, DTML methods, python scripts,
>>>>ZPT) directly to the folder. Or by adding these objects "above" the
>>>>folders and aquiring them which is a type of environmental
>>>>inheritance. In the CMF this is codified in the skins tool which
>>>>contains global methods which can be applied to basically any object
>>>>in the site.
>>>
>>>Great explanation - would you give me a hint on the CMF part ?
>>>Which global methods do you speak of ?
>>
>>The CMF has a "Tool" infrastructure. Tools are persistent objects
>>typically at the top of the CMF site. Tools provide methods and
>>configuration for use by all objects in the site via acquisition. For
>>example, the membership tool (portal_membership), provides methods to
>>access member information and member folders.
>>
>>The portal_skins tool is special in that it actually contains framework
>>and application defined method objects (scripts, templates, etc)
>>organized into layers and configured into skins (which are lists of
>>layers to use). The CMF Site object is a special "Skinnable" folder
>>which allows methods available in the current skin (as described in the
>>skins tool) to be acquired through it. This makes all of the method
>>objects in the skin's layers globally available to all objects in the
>>CMF site. 
>>
>>This solves several problems, one of which is a tendancy of top-heavy
>>hierarchies in zope where lots of objects are in the root because they
>>need to be global. The skin and layer mechanisms allow different sets of
>>methods to be available depending on the application, products
>>installed, site policy and user preferences.
>>
>>-Casey
>>
> 
> 
> Very interesting.  That's what I was looking for.  I will try to extract
> this mechanism from CMF.

Chris McDonough has already released a "standalone" version of the skins 
tool:

   http://plope.com/Members/chrism/standalone_skins

Tres
-- 
===============================================================
Tres Seaver                                tseaver at zope.com
Zope Corporation      "Zope Dealers"       http://www.zope.com