[WikiEN-l] Category intersections would be great :(

Tue Jun 13 16:04:00 UTC 2006

Ilmari Karonen wrote:
> Steve Bennett wrote:
>   
>> - Tag all DSLRs with a new category, replacing the two old ones, and
>> putting the new category as a sub category of both SLR cameras and
>> Digital cameras (doesn't seem clean)
>>     
>
> According to the current guidelines, this is the proper solution.  I 
> don't see what's so unclean about it, anyway -- a DSLR is _defined_ as 
> an SLR that is _also_ a digital camera.  It's no stranger than "Bridges 
> in France" being a subset of both "Bridges" and "Things in France".
>   

It does make it somewhat inflexible, since we have to guess what sorts 
of intersections people care about.  To take your example, we have 
[[Category:Bridges in France]].  We also have categories like 
[[Category:Bridges completed in 1967]].  Now what if I want a list of 
bridges in France completed in 1967?  We could make a new category, 
[[Category:Bridges in France completed in 1967]], but this quickly 
becomes intractable---in principle anyone could want any intersection of 
any combination of attributes, so we'd need an exponential number of 
such categories.  Much cleaner is to tag things with "atomic" categories 
like "bridge" and "in France" and "completed in 1967", and then have a 
way to determine intersections.

-Mark