[Debtags-devel] Proposed Debtags goals for Etch

[Erich Schubert]

Hi Enrico,
Forget about the web interface, I've been admitting that it
despeartely needs a rewrite for more than a year. ;-) I agree that our
notion of facets and tags is very useful to make a better user
interface, too.

> You don't mix axes with values.  They are different.  Axes define a
> direction; values define a position.

Well, I'm a mathematician. Axes don't really exist. But axes is the
wrong term anyway, since we don't have a continuous value anyway. ;-)
I'd more call it a domain or something like that. I refuse to call
anything an axis unless you have a ring to value items on.

I definitely prefer the way of not making a difference between facets and tags.
There is this nice saying by Poincaré, that mathematics is the art of
giving the same name to different things. ;-)
This displays my point of view quite well. I don't see any benefit
from making a difference between tags an facets *except* for the human
aspect in the UI.

> When you say 'works-with::audio', you are giving a position on the
> 'works-with' axis.  When you say 'works-with::audio:mp3' you're giving a
> more precise position.  But in both cases, the axis is still
> 'works-with'.
> 
> Please, tell me this is clear...

No, it is not. This doesn't make works-with::audio really different
from, well, a works-with::audio axis.

We have many domains that do not apply to all packages anyway.
What is the culture of mpg123? Is works-with::audio more or less than
works-with::text?

The whole thing basically breaks down as soon as you allow packages to
have more than one tag (or none at all) within a facet. As long as you
have exactly one tag within a facet thats great. But it just doesn't
work that way.

In my point of view, you have to think of them as sets.
You have a set of packages that "works-with::audio". A subset of that
is the set of packages that "works-with::audio::mp3". And the set of
packages that "works-with::*" is just a superset of that: the set of
packages that is classifyable by the data they work with.
That is a *very* consistent point of view.
In your case, "works-with" by itself doesn't really exist. It's a
group of tags basically. works-with::audio is a group of tags, too.
But it's not a facet. Thats inconsistent! And if you say
"works-with::audio" is a tag, and ...-mp3 is a separate tag, there is
no reason to treat works-with::audio somehow special-

If "works-with::*" would partition the whole space into disjoint sets
it would be great, but it doesn't. And unless "works-with::nothing"
exists - and what does for example xscreensaver work with? - we won't
even have completeness.

That you have certian sets, such as "works-with::*" that are pretty
useless by themselves is a different issue. But doesn't really make
them special. That's just UI.

Of course there is a superset works-with::audio-mp3-or-rasterimage,
too. It's just not useful for the end user. And there is probably no
package in there that is in both audio-mp3 and audio-rasterimage. This
set is probably just as interesting as "works-with::*", so what?

Fortunately, for the information we are interested in, there is no
difference between our points of view, so we can work together just
fine. ;-) But I took this opportunity to remind you that not everyone
agrees with your "there are facets, and below that there are tags"
view. And you have to admit that a second level (and maybe sometimes a
third) is useful.

I also liked the "old" approach of putting certain constraints upon
the branching of the UI very much. This was somehow lost now, with all
the facet-tag things.

best regards,
Erich Schubert
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