[Tagging] Discussion about Multivalued Keys

[Tijmen Stam]

On 27-01-16 18:40, Tod Fitch wrote:
>
>> On Jan 27, 2016, at 9:29 AM, Malcolm Herring <malcolm.herring at btinternet.com> wrote:
>>
>> On 27/01/2016 16:36, Frederik Ramm wrote:
>>> One thing that I would like to see discussed is ordering.
>>
>> There should be allowance for both ordered and unordered multiple values. Whether this is left to the producer/consumer tools or indicated in the tag template is debatable. In the former case the tag definition should be documented to indicate the interpretation of multiple values. In the latter case, a solution such as different delimiter characters would be needed - maybe semicolon for unordered and commas for ordered?
>>
>
> Or, following the example of turn lanes, use semicolon for unordered and vertical bar for ordered. It seems to me that a comma might be too common a character in real world values to have a special use. While an escape mechanism needs to be defined, it would be nice if it were seldom needed.
>
> Assuming, of course, that a delimiter syntax in the value domain is used.

Even within a lanes "namespace", the semicolon-lists have an ordering. 
For example in the destination:lanes, the first item in the semicolon 
(sub)list is meant to be the top one on signs: see the second-last 
example on http://wiki.openstreetmap.org/wiki/Key:destination.