anchor.diff:      | Exe
       | Dll
   
  -
   type AssemblyRef = private AssemblyRef of string
   with
       member this.Value = (fun (AssemblyRef x) -> x)this
  
positive.code:     { Id : PackageId
        Version : PackageVersion }
  
  
  type VcsType = 
      | Git
      | Hg
  
  type Repository = 
      { Name : RepositoryName
        Vcs : VcsType
        Url : RepositoryUrl }
  and RepositoryName = private RepositoryName of string
  with
      member this.Value = (fun (RepositoryName x) -> x)this
      static member Bind(name : string) = RepositoryName (name.ToLowerInvariant())
  and RepositoryUrl = RepositoryUrl of string
  with
      member this.Value = (fun (RepositoryUrl x) -> x)this
  
  type ProjectRelativeFile = ProjectRelativeFile of string
  with
  
negative.code:     static member Bind (file : FileInfo) =  AssemblyRef.Bind (Path.GetFileNameWithoutExtension(file.Name))
  
  type BookmarkName = BookmarkName of string
  
  type BookmarkVersion = BookmarkVersion of string
  
  type Bookmark = 
      { Name : BookmarkName
        Version : BookmarkVersion }
  
  type PackageVersion = PackageVersion of string
  with
  