On Sep 23, 2013, at 10:45 PM, Jochen Topf <joc...@remote.org> wrote: > On Mon, Sep 23, 2013 at 01:44:23PM -0700, Paul Norman wrote: >>> From: Jochen Topf [mailto:joc...@remote.org] >>> Sent: Monday, September 23, 2013 6:51 AM >>> To: talk@openstreetmap.org >>> Subject: Re: [OSM-talk] Who interprets semicolon in tag values? >>> >>> I finally wrote down what I found out about semicolons in tag values and >>> what I think about them. Turns out there isn't much software that >>> interprets them and where it does, only in special cases. Thanks to all >>> who replied and sorry that I haven't mentioned every case in my blog >>> post. >>> >>> http://blog.jochentopf.com/2013-09-23-semicolons-in-osm-tags.html >> >> It's worth noting that when two objects are merged in iD it splits the >> tag's value into lists at semicolons, merges the lists from the two objects, >> >> and then turns the resulting list into a semicolon separated list. See >> https://github.com/systemed/iD/issues/943. I believe iD is actually the >> only editor that attempts to support semicolon lists in tags. JOSM and >> P2 emit them, but don't interpret them. >> >> This of course doesn't avoid contradictory tags like tiger:separated=yes;no >> but it at least avoids tiger:separated=yes;no;no;no;yes;no;yes;... > > This would be better if semicolons always indicated sets of values, which, > as I describe in my blog post, is the wrong assumption. For 'ref' tags this > is probably the right behaviour, for about anything else it is wrong. > > IMHO editors should either do something clever, if they know the specific > tag and how it is used, or fall back to forcing the user to make a decision.
It would be great if support for semicolons was opt-in for tags. If a particular tag supports semicolons it should be documented along with the appropriate semantics (ordered vs. unordered, etc.) during merges, and with a hint in taginfo that editors could follow. Tags that don't opt-in should not get special treatment. _______________________________________________ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
