Are "identity" zoom functions allowed?

[lucaswoj]

From @jfirebaugh on November 30, 2016 2:7

    {
      "id": "fill",
      "type": "fill",
      "source": "source",
      "source-layer": "layer",
      "paint": {
        "fill-opacity": {
          "type": "identity"
        }
      }
    }

Is this allowed?

Copied from original issue: mapbox/mapbox-gl-style-spec#603

[lucaswoj]

I can't think of a reason why we shouldn't allow this unless it adds implementation complexity.

[lucaswoj]

From @jfirebaugh on November 30, 2016 19:13

It will add four additional rows to #604, which translates to implementation complexity for gl-native.

[jplante]

Unless there is another way to handle circle-radius as a distance, we would like this feature:

For example - ALA Leaflet's Circle and CircleMarker - where the radius is based on either distance or pixels - we could use this for setting different radius for a Circle based on data identity attributes

[jplante]

According to this, there is no other way to handle circle-radius as a distance:
#2525