[Grok-dev] Traversing

[Martijn Faassen]

Christian Theune wrote:
> I just noticed that our traverser does not know what to do if traverse()
> isn't defined.
> 
> I stumbled over that when I switched our wiki to grok.Container. I
> talked to Philipp shortly on IRC and he proposed not to do fallback to
> attribute/dict access.
> 
> I somewhat agree. However, we have to define how grok.Container behaves.
> 
> The most simple solution I can imagine would be to define a default
> traverse() on the container that does the dict lookup.

I'm not sure what you are proposing as the behavior.

What I expect traverse to do:

if not on a container, return the object I want to traverse to, or None 
if there's no object to traverse to, in which case the end-user should 
see a 404.

if on a container, I want to define the object I want to traverse to, or 
None if there's no object to traverse to. In that case, the container 
falls back on its normal traversal behavior and tries to traverse into 
itself.

if traverse isn't defined, then Containers will behave as they do 
normally, so allow traversal into their contents.

Since inside the container traverse() I can inspect the contents of the 
container, this allows me to do anything I want - either traverse into 
my own traversal space, or the container's if there's something 
available, or neither.

Regards,

Martijn