[Mapcss] eval and set

[Komяpa]

>    way[highway=primary] {z-index: eval(tag(layer)+0.2);}
> should do just fine. What do you think? I think, I'll make it work that way
> for now.
I think it's not a good idea. IMHO, casings for each layer should be
restarted, to get, for example, correct rendering for bridges:
http://latlon.org/~komzpa/screenshots/kothic-bridges.jpeg

Also, I see you're using non-integer z-indexes. That might break some
software that has rendering for each zoom using BASIC-like "for i=1 to
10" loop counter. I guess this should be noticed in spec. Whether we
allow non-integer z-indexes

-- 
Komяpa aka Darafei Praliaskouski
xmpp:me at komzpa.net mailto:me at komzpa.net