I see your point Martin. So all we need now (for your example) is a
documented map from shop=tobacco to a list of sells:*=* tags which are
default for shop=tobacco. One would reasonably expect
sells:cigarettes=yes, sells:pipe_tobacco=yes and
sells:rolling_tobacco=yes, but I am not sure about sells:chewing_tobacco
or actual devices such as rolling machines and pipes. The product
categories may also appear with other types of shop, like
shop=supermarket might have sells:pipe_cleaners=yes if anyone finds it
necessary to tag that. So we have a simple, flat list of product
categories, with a 1:n mapping from shop type to product categories.
Tobacco shops
* Main tag: shop=tobacco
* Typical product categories and defaults for this type of shop:
** cigarettes (yes)
** pipe_tobacco (yes)
** rolling_tobacco (yes)
** chewing_tobacco (unknown)
** snuff (unknown)
** pipes (unknown)
** pipe cleaners (unknown)
** rolling machines (unknown)
Back to our chemists/drugstores/pharmacies, I would suggest
prescription_only_medicines, pharmacy_only_medicines, general_medicines,
plus a bunch of others to represent the wide variety of things you get
in "drugstores" like household_cleaning, hair_products, etc.
The "art" is going to be choosing these product categories so they are
a) not so specific that the list gets too long and unwieldy and b) not
too high-level that they add too little distinction between the shop
types ("medicines" would probably be an example of this).
//colin
On 2015-11-02 12:17, Martin Koppenhoefer wrote:
> 2015-11-02 11:45 GMT+01:00 Colin Smale <colin.sm...@xs4all.nl>:
>
> On 2015-11-02 11:26, Martin Koppenhoefer wrote:
>
> 2015-11-02 11:16 GMT+01:00 Colin Smale <colin.sm...@xs4all.nl>:
>
> The second issue is that the value part of the KVP is redundant - the
> presence of the key is enough.
>
> not if you consider values like "no" and "only".
The "no" would be indicated by the absence of the tag (we are not going
to add a sells:*=no for everything it doesn't sell, are we?)
The "only" would be indicated by the absence of any other sells:*=* tag
that's the difference between explicit and implicit mapping. If you are
explicit, you know that it should be like that, if you rely on the
absence of information / tags you might fall on your nose because the
data wasn't complete etc.
For some stuff it might sense to use the "no" to avoid
misinterpretations by wrong asumptions, e.g. shop=tobacco,
sells:cigarettes=yes, sells:cigarette_tobacco=no
or highway=motorway_link, oneway=no.
also: sells:vegetables=only
sells:cabbage=yes
sells:carrots=yes
...
etc.
Cheers,
Martin _______________________________________________
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