anchor.diff:                  inner {opts with OutputPath = Some outPath } tail
               | "--nobeam" :: tail ->
                   inner {opts with NoBeam = true } tail
  +            | ("-a" | "--dump-ast") :: tail ->
  +                inner {opts with DumpAst = true } tail
               | files ->
                   {opts with Files = files }
   
           inner { OutputPath = None
                   NoBeam = false
  +                DumpAst = false
                   Files = [] } argv
           |> Compile
   
  
positive.code:             0
          | Compile { Files = files
                      OutputPath = outPath
                      NoBeam = noBeam } as c ->
              let outDir =
                  match outPath with
                  | None ->
  
negative.code:         OPTIONS:
              -o | --output       set output directory
              --nobeam            do not compile core files to beam
              -a | --dump-ast     prints the fsharp typed AST to stdout
  
      fez erl <args>
          Launches the erlang shell with the appropriate search paths set.
  