mapcss2osmose: support for multi-element rules (parent selectors and such)

[Famlam]

Currently our mapcss only supports "single element"-rules. Rules with e.g. parent/child/link selectors (e.g. way[x] > node[y]), containment selectors (e.g. node[x] ∈ area[y]), connection pseudo-classes (e.g. :unconnected) or parent/child-expressions (e.g. parent_tag(...)) are all ignored at the moment.

It would be great to also support them in Osmose. Most likely this'll have to be via SQL queries.

The biggest challenges I'd expect:

• efficiency
• connection with class selectors (which may also be shared with single-element rules, e.g.

node[some_selector] {set x;}
way[z] > node!.x {throwWarning: "X";}

Just filing this issue to also have it on the issue tracker.

[frodrigo]

I already have a partial implementation of that some where...

[frodrigo]

I already have a partial implementation of that some where...

I found it in /home/fred/osmose-backend/mapcss/mapcss2osmose-osmosis.py on osm110