anchor.diff:  
   // NuGet dependency
   "Build"
  +==> "EnsureDeploy"
   ==> "NuGetMain"
   ==> "NuGetFSharp" <=> "NuGetGraphics"
   ==> "NuGet"
   
   // Zip dependency
   "Build"
  +==> "EnsureDeploy"
   ==> "Zip"
   
   // Deploy dependency
  
positive.code:    let assemblyPath = outputDir % assemblyName
     let version = getMainAssemblyVersion assemblyPath
     let nuspecPath = % (sprintf "%s.nuspec" projectName)
     ensureDirectory deployDir
     NuGetPack (updateNuGetParams version) nuspecPath
  Target "NuGetMain" (fun () ->
     pack rdotnetMain
  
negative.code:    |> Seq.collect getProducts
     |> Copy outputDir
  )
  Target "EnsureDeploy" (fun () ->
     ensureDirectory deployDir
  )
  
  let getMainAssemblyVersion assemblyPath =
     let assembly = Assembly.LoadFrom (assemblyPath)  // cannot get attributes with ReflectionOnlyLoadFrom
  