[Tagging] Reviving the conditions debate

[Ilari Kajaste]

(Sorry for a possible double-post, this message I sent earlier today
(7:52:26 UTC) hasn't yet appeared for some reason.)

On 2012-06-15 09:07, Colin Smale wrote:
> The bulk of the discussion up to now has been about "access" type tags,
> producing a boolean value: can I or can't I use this road under the
> given conditions. Why limit it to boolean? Why not address the use case
> of "what is the maximum speed for vehicle X under these conditions"
> (returning a number) or "what are the opening hours of this amenity on a
> given date" (returning a string which can be parsed as a date, or
> returning an object containing some more date objects if you want to go
> further)?

To my understanding, the "Extended conditions" proposal isn't in any
way limited to boolean values. In fact, even the examples have
numerical values:

maxspeed:hgv = 120
maxspeed:hgv:(Sa,Su) = 80

Also opening_hours already implements a complex value-string for
multiple values. Using Extended conditions would make it a bit more
clear to read, though. For example:

opening_hours = Mo-Fr 8:00-16:00; Sa 12:00-16:00; Dec 20-Jan 06 Mo-Fr
12:00-18:00; Dec 20-Jan 06 Sa 12:00-14:00; Jan 01 off

could become something like

opening_hours = Mo-Fr 8:00-16:00; Sa 12:00-16:00
opening_hours:(Dec 20-Jan 06) = Mo-Fr 12:00-18:00; Sa 12:00-14:00
opening_hours:(Jan 01) = closed

or even

opening_hours:(Mo-Fr) = 8:00-16:00
opening_hours:(Sa) = 12:00-16:00
opening_hours:(Dec 20-Jan 06 Mo-Fr) = 12:00-18:00
opening_hours:(Dec 20-Jan 06 Sa) = 12:00-14:00
opening_hours:(Jan 01) = closed

Though the given example is unusually complex, so it's not a good
example of a common case. And as a sidenote I'm not sure OSM database
is even the right place for such detailed opening hours, but that's a
whole other discussion.

--
    - Ilari Kajaste -

E-Mail: ilari.kajaste at iki.fi
WWW: http://iki.fi/ilari.kajaste