anchor.diff:          let projectFile = prjDir |> GetFile (AddExt (project.ProjectGuid.ToString("D")) Targets)
           xdocSaver projectFile content
   
  -let ConvertProject (xproj : XDocument) (project : Project) (nugetFiles) =
  +let ConvertProject (xproj : XDocument) (project : Project) (nugetFiles : Set<AssemblyRef>) =
       let filterProject (xel : XElement) =
           let attr = !> (xel.Attribute (NsNone + "Project")) : string
           attr.StartsWith(MSBUILD_PROJECT_FOLDER, StringComparison.CurrentCultureIgnoreCase)
  
positive.code:         afterItemGroup.AddAfterSelf (import)
      cproj
  
  let ConvertProjectContent (xproj : XDocument) (project : Project) (package2Files) =
      let nugetFiles = package2Files |> Seq.filter (fun (id, _) -> project.PackageReferences |> Seq.contains id)
                                     |> Seq.map (fun (_, files) -> files)
                                     // TODO: should be fold with Set.union probably
                                     |> Seq.concat
                                     |> set
  
      let convxproj = ConvertProject xproj project nugetFiles
      convxproj
  
  let ConvertProjects (antho : Anthology) (package2Files) xdocLoader xdocSaver =
      let wsDir = WorkspaceFolder ()
      for project in antho.Projects do
          let repoDir = wsDir |> GetSubDirectory (project.Repository.Print())
  
negative.code:     // for each package, get all assemblies
      let package2Files = antho.Packages 
                          |> Seq.map (fun x -> (x.Id, Package.GatherAllAssemblies x.Id))
                          |> Map
  
      ConvertProjects antho package2Files XDocumentLoader XDocumentSaver
  