[Zope3-dev] views/foo versus context/@@foo

[Martijn Faassen]

Hi there,

Currently in Zope 3 in its page templating engine there is a 'views' 
name defined that can be used to access a particular view in TALES, like 
this:

views/foo

or

python:views['foo']

I heard that this is deprecated in favor of:

context/@@foo

or presumably in Python, something like:

python:path('context/@@foo')

I have a few comments to make.

A cursory grepping of the Zope 3 codebase saw a lot of instances where 
instead of:

context/@@foo

we see

context/foo

This works, until there's actually a name clash with something called 
'foo' in content space, like the user adding an object called 'foo'. 
That's an annoying type of bug; code should just not work or work fine, 
instead of having a booby trap waiting for it.

You can tell people to always use @@ but that's a weak way to prevent 
bugs. You need to tell people. People need to read it. People need to 
understand the severity of the problem and decide to use @@. And then 
finally people need to actually not accidentally forget.

If instead you told people to always use 'views' if they want a view, 
things are a lot easier to do right.

Of course 'views' has a problem in that it is named rather confusingly 
similar to 'view'. Perhaps a new, better, term for 'views' needs to be 
devised.

Regards,

Martijn