anchor.diff:  
           //type HGrammar<'TInt> =
           //    HGrammar of 'TInt * list<'TInt * list<'TInt>>
  -
  -    let ast2graph (tree: Yard.Generators.Common.ASTGLL.Tree<Token>) =
  -        tree.AstToDot indToString tokenToNumber tokenData "x.dot"
  -        System.IO.File.ReadAllText "x.dot"
   
       let parse grammar graph = buildAbstractAst<Token> grammar graph
   
  
positive.code:         | And(_, _) when snd range = 0 -> [""]
          | _ -> []
      
      let seqFilter (xs: list<string>) : string[] =
          let mutable ys = []
          for x in xs do
              if not <| List.contains x ys then
                  ys <- x :: ys
          Array.ofList ys
      
      let markGraph (vc: int) (mapInput: Map<int * int, Nuc>) (markers: list<int * int>): Graph =
          {
  
negative.code:                 | AndA -> And (genTree j)]
                  *)
          tree'text//genTree 0
  
      type ExtensionTree =
          | Extension of int * int
  