anchor.diff:  
           let containsRange number = 
               tokenToPos tokens.[number]
  -            |> Seq.exists (fun range -> range = now)
  +            |> Seq.exists ((=) now)
   
           let rec handleFamily (family : OtherFamily) = 
               family.nodes.doForAll 
  
positive.code:                     let otherChildren = 
                          if ast.other = null
                          then null
                          else Array.map (fun child -> processFamily child) ast.other
  
                      let newAST = new OtherAST (fstChild, otherChildren)
                      dict.Add (ast, newAST)
  
negative.code:                 
                              children := newElem :: !children
                  
                          oldNodes.doForAll handle
                          new OtherNodes(!children |> List.rev |> Array.ofList)
                  
                  otherFamily.ReplaceNodes newNodes
  