On Sat, 03 Jun 2006 17:27:59 -0400, Anthony DiPierro wrote:
Agreed. Still: can you give some specific examples of wonderful things that could be done but are not possible now? That would tell us what problem you are trying to solve.
I've personally run into this when trying to automatically create, for example, a list of all Wikipedia articles on people. You can't just start at [[category:people]] and work your way down, because you wind up going to [[Category:Women]] (fine, all women are people) then [[Category:Feminine hygene]] (bad).
Okay, that's equivalent to Steve's Amelie-Paris relation. I agree that's a problem.
Categories based on such intersections of attributes are conceptually bad. Look at the categories for an article like [[Marie Curie]]: She's French three times, female four times, Polish four times (not counting "Natives of Warsaw"), etc. Why not create [[Category:Polish women who were born in 1867 and died in 1934 and won a Nobel Prize in Chemistry and in Physics]]?
Because there would only be one person in that category.
That's why nobody made it, but not why it shouldn't be done.
It would be nigh impossible to do well because once we start combining attributes to create new categories, we are looking at maintaining links between articles and an exploding number of subcategories.
But even if we maintained a complete and up-to-date system of subcats, we'd still make it hard for people to find articles using categories. For some fairly sensible reasons, the rule is to include articles only to the subcategory, but not to the parent. There is no way to list articles based on a subset of criteria (the articles in subcategories are effectively hidden on separate pages which is only helpful if you know which one to pick).
If the category system could effectively build these intersection categories on the fly, I'd agree. But the category system can't currently do that. (And it's been around a reasonably long time, with that as an obvious flaw, and no one has fixed it.)
You are right, we can't effectively build these intersection categories on the fly at the moment, but we _could_ automatically create or update such intersection categories if the categories weren't the mess that Steve and you describe. Kind of like the search index.
Attributes: The category exists to denote some very specific small detail of a subject, such that it would be conceivable to have dozens or more such categories on an article. Examples: 1943 deaths, Living persons, Winners of Nobel Peace Prize, etc. These tend to hierarchies that start strict then end up fuzzy. Eg, 1943 deaths is only in 1943 and "1940s deaths", and these have parent categories of "1940s","Years" and so forth, eventually ending up in "History", whereupon things become chaos.
There is no way to make hierarchies not suck, especially if you have to maintain them manually (as we do now). Don't try to impose hierarchies unless they emerge quite naturally from the subject.
I made a proposal. All subcategories of attributes must be a subset of the parent attribute. Seems like a perfectly reasonable way to make hierarchies not suck.
The devil is in the details.
For instance, how do you connect the districts of Paris to the category Paris? What is a subset of the parent attribute "Paris": "Districts of Paris", or "Quartier Latin", or neither? Does it bother you if the article on a French district is now in a subcategory of "Capitals in Europe"?
Or going back to [[Category:Women]]: You could declare that only articles on instances of women (i.e. biographies) can ever be under that category, and that only sets of such articles can ever be subcategories of the category women. -- You could even create a separate [[Category:Woman]], subcategories like "female reproductive organs" containing articles like uterus. -- But how would you express the undisputed relationship between female human beings and your example [[Category:Feminine hygiene]]? How about [[Category:Women's rights]]? Add an umbrella cat "Somehow related to women" maybe?
Roger