[Zope-CMF] [dev] ActionProviderBase redux proposal

[yuppie]

Hi!


Background:

There are two types of Actions: Simple dictionaries and the newer and 
more powerful ActionInformation objects.

The methods for listing Actions return always simple dictionaries. 
Creating dicts from ActionInformation objects is done late in the 
process because resolving TALES expressions is expensive and some 
Actions are filtered out before returning the list.

In CMF 1.4 the Actions Tool did the filtering and created the dicts, in 
CMF 1.5 alpha ActionProviderBase does it. In CMF 1.4 the Actions Tool 
had different code for both kinds of Actions, now ActionProviderBase has 
the code for ActionInformation Actions and OldstyleActionProviderBase 
the code for dict Actions.


Proposal:

Add a new ActionInfo class that implements a 'lazy' dict. This way we 
can create the dict at the beginning of the process *and* resolve TALES 
expressions only if needed. This class could also be used as a wrapper 
for dict Actions and set defaults for keys that are not defined in these 
Actions.

This way we can use the same code for both Action types and remove 
OldstyleActionProviderBase again.

This would also be a first step for improving DCWorkflow Actions: Both 
kinds of Actions could be mixed, so the Workflow Tool could return dicts 
from old hardcoded workflow definitions like CMFDefault/DefaultWorkflow 
and ActionInformation based Actions from DCWorkflow.


That idea is inspired by <http://collector.zope.org/CMF/232> and should 
make resolving it easier.


If that sounds like a good idea I'd like to implement it before 1.5 beta 
is released.

Cheers,
	Yuppie