anchor.diff:      let ColorType name convName convType =
           let chained args = args ^-> Rgb
           Class name
  -        |+> Protocol (
  +        |+> Instance (
               name |> Seq.map (fun n ->
  -                string n =@ Int :> CodeModel.Member
  +                string n =@ Int :> CodeModel.IClassMember
               )
               |> List.ofSeq
           )
  -        |+> Protocol [
  +        |+> Instance [
               "brighter" => chained !?Float?k
               "darker"   => chained !?Float?k
               convName   => O ^-> convType
  
positive.code:         let self = Type.New()
          Class "Map"
          |=> self
          |+> Protocol [
              "has"     => String?key ^-> Bool
              "get"     => String?key ^-> Float
              "set"     => String?key * Obj?value ^-> O
  
negative.code: 
              ]
              Class "d3.geom"
              |+> Static [
                  "voronoi"  => O ^-> Voronoi
                  "quadtree" => O ^-> Quadtree
                  "polygon"  => (!|Float2T)?vertices ^-> Polygon
                  "hull"     => O ^-> Hull
              ]
              Class "d3.behavior"
              |+> Static [
                  "drag" => O ^-> Drag
                  "zoom" => O ^-> Zoom
              ]
  