             function(x) {
               x = Number(x);
               if(isNaN(x)) return null;
-              x = #{floorExpresion};
-              return x;
+              return #{floorExpresion};
             }
             """
 


      when 'within'
        [r0, r1] = filter.range
        if typeof r0 is 'number' and typeof r1 is 'number'
          {
            type: 'javascript'
            dimension: filter.attribute
            function: "function(a){return a=~~a,#{r0}<=a&&a<#{r1};}"
          }
        else
          throw new Error("apply within has to have a numeric range")

      when 'not'
        {

            return {
              type: 'selector'
              dimension: filter.attribute
              value
            }
          ), this)
        }
