By year by demand, reusing ID

[ppKrauss]

Final decision? ... And change lookup.csv first suggestion...

It is "by demand" because only will be registered when in use by a curated stable dump.

It is "reused" because we can reuse the usual element's ID (osm_id)... So, the perma_id is an alphanumeric string with the syntax:

Perma_ID ::= Year OsmType OsmID
Year     ::= [0-9]+           /* year of the "standard */
OsmType  ::= 'r' | 'w' | 'n'  /* relation or way or node */
OsmID    ::= [0-9]+           /* full positive integer in use at that year */

Notes: Year not changes, only when OSM changes all infrastructure, so perhaps each 5 or 10 years... Can be a counter of "perma_id version", and changes only for newer geometries (thereare are a track-of-original mechanism based on hashes or other attributes). OsmID can be translated to base36 lower (to be compressed), and OsmType to upper case.