Zope 3 wiki → Developer Info → Proposals →
last edited 11 months ago by nederhoed
created: 2005-10-05

Simplify macro registration

Provide ZCML directive for macro registration instead a python class and smplify the lookup via a macros: TALES expression and a IMacros adapter.

Status

IsProposal

Author

Roger Ineichen (dev@projekt01.ch)

Problem/Proposal

Right now we define the macros in ZPT like this: 

        <metal:block define-macro="page">

and use the macro like this: 

        <html metal:use-macro="context/@@standard_macros/view">

This is really weird because there is no relation in the naming.

The relation is done in a python class e.g. StandardMacros? which is inherited from the class Macros: 

        class Macros(object):
            zope.interface.implements(zope.interface.common.mapping.IItemMapping)

            macro_pages = ()    
            aliases = {
                'view': 'page',
                'dialog': 'page',
                'addingdialog': 'page'
                }

            def __getitem__(self, key):
                key = self.aliases.get(key, key)
                context = self.context
                request = self.request
                for name in self.macro_pages:
                    page = zapi.getMultiAdapter((context, request), name=name)
                    try:
                        v = page[key]
                    except KeyError:
                        pass
                    else:
                        return v
                raise KeyError(key)

        class StandardMacros(BrowserView, Macros):
            macro_pages = ('my_macros, 'other_macros')

This class is registered as a page: 

      <browser:page
          for="*"
          name="standard_macros"
          permission="zope.View"
          class=".standardmacros.StandardMacros"
          layer="tiks.skins.basic.basic"
          allowed_interface="zope.interface.common.mapping.IItemMapping" 
          />

Where allows to lookup macros in ZPT like: 

        <html metal:use-macro="context/@@standard_macros/my_macros">

Goals

I like to simplify this with a own directive for registering macros like: 

      <browser:macros
          for="*"
          name="standard_macros"
          macros="page"
          aliases="view:page dialog:page"    (only if we need to support the mapping)
          permission="zope.View"
          template="template.pt"
          layer="tiks.skins.basic.basic" 
          />

Then register a adapter where we can lookup like this: 

      zapi.getMultiAdapter((context, request), IMacros, name='standard_macros')

This adapter lookup is a part of the TALES expression where we register. The new style macro lookup will use the TALES expression and call macros like: 

        <html metal:use-macro="macros:standard_macros/my_macros">

Or if we can get rid of the mapping we can use the macro call like:

Why do we need this?

I like views but it seems to me, that the view namespace get more and more used as a new aquisition concept for z3. Not everything is a view because we can adapt it to context and request. Macros are a good sample of this. Right now, macros provide to much and get lookuped via a second view hook. This will slow down and is not needed.

Risks

Yet another ZCML directive



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