GeoServer CSS rotation with env and property name

Question

Using GeoServer CSS extension

 mark-rotation:  [env('rot',2)];

ends in

    <sld:Rotation>
        <ogc:Function name="env">
            <ogc:Literal>rot</ogc:Literal>
            <ogc:Literal>2</ogc:Literal>
         </ogc:Function>
     </sld:Rotation>

How should my style look like to add a property name to rotation:

 <sld:Rotation>
    <ogc:Add>               
    <ogc:PropertyName>mystyle</ogc:PropertyName>
       <ogc:Function name="env">
          <ogc:Literal>rot</ogc:Literal>
          <ogc:Literal>2</ogc:Literal>
       </ogc:Function>
    </ogc:Add>
  </sld:Rotation>

I have tried

 mark-rotation:  [env('rot',2),mystyle];
 mark-rotation:  [mystyle],[env('rot',2)];

Answer 1

To produce a rotation of ( the rot variable or 2 ) plus the value of the property mystyle you should use:

mark-rotation: [env('rot',2)+mystyle]; 

To generate SLD that uses rot, followed by mystyle, or 2 you should use something like (and I haven't tested this). If it doesn't work you can check the syntax page:

mystyle is null {
  mark-rotation:  [env('rot',2)]
}
mystyle is not null {  
  mark-rotation: [mystyle];
}