[OSM-dev] Disallowing certain characters in tag keys
osm at tobias-knerr.de
Sat Oct 16 23:45:41 BST 2010
Jochen Topf wrote:
>> This proposal  moves values into the key to describe conditions.
>> (Although you could argue, it should be done like that anyway...)
> I think thats a misguided use of tag keys probably invented by people who have
> never actually tried to write code that tries to interpret OSM tags.
No speculation required, I'm the one who is to blame for that proposal.
Before I finished the text that's still in the wiki, however, I /did/
write an experimental implementation* for this syntax, as well as an
alternative syntax, to find out whether the ideas could work from a
developer's perspective. I didn't encounter any significant problems.
In retrospect ... well, maybe it wasn't the best of ideas to write that
implementation based on the GraphView plugin for JOSM. After all, I
figure that working on a comparably small in-memory dataset makes a
significant difference for the way you would deal with keys. Add to this
that I didn't have to deal with any web issues, or in fact any interface
between programs at all (-> no encoding issues), and it probably wasn't
remotely a representative development experience.
Unfortunately, it seems this will produce exactly the outcome I didn't
intend at all: more "variety" in tagging. People will continue to use
those parts of the proposal that don't require special characters
(maxspeed:wet, :forward and the like), so we will use completely
different solutions for simple and for more complex cases.
Well, I'll file this as "failed attempt of overzealous newbie to build
* I ended up never publishing the implementation, though - not due to
condition handling itself, but because I never got around to implement a
proper opening_hours parser. Turns out that's actually more work than
the entire rest of the syntax.
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