anchor.diff:                                  |> Pretty.Types.commaSep ]
       | Other e -> Pretty.Types.String e
   
  +/// Prints an ok result to stdout.
  +let printOk pOk pBad =
  +    pairMap pOk pBad
  +    >> function
  +       | (ok, []) -> ok
  +       | (ok, ws) -> Starling.Pretty.Types.vsep [ ok
  +                                                  VSkip
  +                                                  Separator
  +                                                  VSkip
  +                                                  headed "Warnings" ws ]
  +    >> Starling.Pretty.Types.print
  +    >> printfn "%s"
  +
  +/// Prints an err result to stderr.
  +let printErr pBad =
  +    pBad >> headed "Errors" >> Starling.Pretty.Types.print >> eprintfn "%s"
  +
   /// Pretty-prints a Chessie result, given printers for the successful
   /// case and failure messages.
   let printResult pOk pBad = 
  -    either (pairMap pOk pBad >> function 
  -            | (ok, []) -> ok
  -            | (ok, ws) -> 
  -                Starling.Pretty.Types.vsep [ ok
  -                                             VSkip
  -                                             Separator
  -                                             VSkip
  -                                             headed "Warnings" ws ]) (pBad >> headed "Errors")
  +    either (printOk pOk pBad) (printErr pBad)
   
   /// Shorthand for the HSF stage.
   let hsf = bind (Starling.Horn.hsfModel >> mapMessages Error.HSF)
  
positive.code:         if opts.raw then (sprintf "%A" >> Starling.Pretty.Types.String)
                      else printResponse opts.showModel
      printResult pfn (List.map printError) starlingR
      |> Starling.Pretty.Types.print
      |> printfn "%s"
      0
  
  [<EntryPoint>]
  
negative.code:     match CommandLine.Parser.Default.ParseArguments<Options> argv with
      | :? Parsed<Options> as parsed -> mainWithOptions parsed.Value
      | :? NotParsed<Options> as notParsed -> 
          2
      | _ -> 
          printfn "parse result of unknown type"
  