[Zope-CMF] Differences in CMF Expression contexts (was: Caching policy manager binding inconsistency)

[Jens Vagelpohl]

I've done a quick survey of expression contexts used for TAL 
expressions in CMF CVS-HEAD/1.6. There are five places [1] that build 
these contexts or act as such.

There are differences in naming for the current user, the containing 
folder, the content object, and associated URL strings pointing to the 
content object. DCWorkFlow sticks out in this group because it has a 
zope-ish naming convention rather than a CMF-ish schema, probably 
because it [was|is] designed to be usable outside of the CMF, so I will 
exclude it here. That leaves me with the following big difference:

- the content object:
	- CachingPolicyManager: "content"
	- CMFCore.Expression: "object" _and_ "here"
	- CMFCore.utils: "object"
	- CMFCore.ActionInformation: "content"

Suggestion: Standardize on either "object" or "content" in all of them. 
This implies that URL strings that become part of the expression 
context and point to the object in question get named accordingly 
("object_url"/"content_url"). This standardization would include 
documentation updates and, where possible, noting the available 
expression context members on the form that is used to input the TAL 
expression.

Question: Who would like to see standardization, and from those, what 
name should be chosen?

jens

[1]
- CMFCore.CachePolicyManager.createCPContext
- CMFCore.Expression.createExprContext
- CMFCore.utils.getActionContext (marked as deprecated)
- DCWorkflow.Expression.createExprContext
- class CMFCore.ActionInformation.oai