[Developers] attributes of properties?

[Alec Flett]

John Pritchard wrote:
>
> Hi,
>
> Skipping a personal introduction, I'll jump right into some first 
> thoughts on a look into MetaWeb. 
>
> I like it, but.. MetaWeb appears (to me) to be in need of some "out of 
> band" "attributes of properties".  This is usually where "type" would 
> live, but is best illustrated in the MetaWeb case by "key".  It seems 
> to me, in my humble opinion (ie, without much study), that the "key" 
> thing is a bit messy.
>
Can you be more explicit about this? When you say "attributes of 
properties" what kind of attributes are you talking about? Properties 
themselves have a number of properties on them, including 
"expected_type" which is the type that the given value should have (i.e. 
so that /film/film/directed_by has an expected_type of /film/director)

One thing that may be confusing here is that expected_type is not 
strongly enforced - it's really more of a hint to allow the query 
language to make assumptions about property values, which allows the 
syntax to be short when the expected_type of a property value does in 
fact match. I can explain this further if you want...

the "key" thing may also be confusing because "key" is essentially a 
backpointer to the enclosing namespace. i.e. the "key" of 
/wikipedia/en/Anarchism is /wikipedia/en. Since a "namespace" is really 
just node that has a "keys" property, not all items in an id path are 
namespaces. For example, /wikipedia/en/Anarchism is not a namespace, but 
/wikipedia/en is.

Alec