[Mapcss] Questions concerning tests

Andrew Shadura bugzilla at tut.by
Wed Sep 18 08:09:14 UTC 2013


On 16 September 2013 21:32, Stephan Bösch-Plepelits
<skunk at xover.htu.tuwien.ac.at> wrote:
> The MapCSS 0.2 specification[1] says the following about unary tests:
>   way[highway]       /* Matches against all ways with the highway tag set */
>   way[!highway]      /* Matches against all ways with the highway tag not set (or set to no/false) */

> Question: Wouldn't it be more logical if the first statement does not match
> ways with the highway tag set to no or false?

Well, the idea behind this selector test was to make it easy to tell
oneway=yes/1/-1 from oneway=no or missing oneway, for example. This
allows for simpler conditions in selectors. Probably, way[highway]
form shouldn't match oneway=no. Also, probably 0 should be treated the
same as no.

However, JOSM approach to MapCSS is slightly different: they decided
to remove this boolean condition. So in JOSM way[highway] matches
highway=no and way[!highway] doesn't match highway=no.

I don't know which approach is better, but we need to decide somehow.

WBR, Andrew

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