[Mapcss] Interaction of exit; and layer specifiers

[Komяpa]

2012/4/28 Thomas Davie <tom.davie at gmail.com>:
> Hi Guys,
>
> I'm just implementing exit; in OpenStreetPad to allow stylesheet authors to quickly short circuit out boring objects...  What I'm not completely clear on is exactly what the interaction between exit; and layer specifiers.  What would people expect to be the style generated for each layer (given a way tagged highway=motorway) here?
>
> way[highway=motorway] :: A
> {
>  width: 4pt;
>  z-index: 0;
>  color: red;
>  exit;
> }
>
> way[highway=motorway]
> {
>  width: 2pt;
>  z-index: 2;
>  color: green;
> }
>
> way[highway=motorway] :: A
> {
>  color: blue;
> }
>
> Should the exit; short circuit *all* style generation, or only generation for layer A?  Should it not have any effect in a declaration for a layer?  The sane styles I could see generated would be:
> 1) base layer: no style.  layer A: red, 4pt, z-index 0.
> 2) base layer: green, 2pt, z-index 2.  layer A: red, 4pt, z-index 0.
> 3) base layer: green, 2pt, z-index 2.  layer A: blue, 4pt, z-index 0.
>
> Which would you guys say is correct?

1 and 3.

1 is correct for renderers supporting "exit";
3 is correct for renderers not supporting "exit".



-- 
Darafei "Komяpa" Praliaskouski
OSM BY Team - http://openstreetmap.by/
xmpp:me at komzpa.net mailto:me at komzpa.net