anchor.diff:              if this.Anchors.ContainsKey s then this.Anchors.[s] |> Some
               else None
   
  -        member this.MarkParseRange pss =
  -            this
  -            //let filterRange msl =
  -            //    msl
  -            //    |> List.filter(fun (m:MessageAtLine) -> m.Location >= pss.Location && m.Location <= this.Location)
  -            
  -            //(this.Messages.Error |> Map.toList |> List.map snd |> List.collect id) @ this.Messages.Warn
  -            //|> filterRange
  -            //|> List.fold(fun (s:ParseState) i -> s.AddCancelMessage (i.Location)) this
  -
  -
  -        //[<DebuggerStepThrough>]
  +        [<DebuggerStepThrough>]
           member this.SkipIfMatch p = 
               match (HasMatches(this.Input.Data, p)) with
               |   (true, mt)  -> 
                   let nxt = this.Advance()
  -                (nxt.TrackPosition mt).MarkParseRange this
  +                nxt.TrackPosition mt
               |   (false, _)    -> this
           
           member this.SetStyleContext cn = { this with c = cn}
  
positive.code:             let (n, psr) = pso.Data
              AddCancelMessage (ps.Location) psr
              FallibleOption.Value(n,psr)
          |   _ -> pso
  
      let MarkParseRange (pss:ParseState) (pso:FallibleOption<_>) =
          match pso.Result with
          |   FallibleOptionValue.Value -> 
              let (n, (psr:ParseState)) = pso.Data
              FallibleOption.Value(n, psr.MarkParseRange pss)
          |   _ -> pso
  
      let AddErrorMessageDel m (ps:ParseState) = ParseState.AddErrorMessageDel ps m 
  
negative.code:                 let prs = prs.SkipIfMatch (OPT(this.``s-separate`` prs))
                  let commaPattern = this.``c-collect-entry`` + OPT(this.``s-separate`` prs)
                  match prs with 
                  |   Regex3(commaPattern) (_, prs2) -> ``ns-s-flow-seq-entries`` prs2 lst
                  |   _ ->  
                      CreateSeqNode (NonSpecific.NonSpecificTagQM) (getParseInfo ps prs) lst
                      |> this.ResolveTag prs NonSpecificQM (prs.Location)
  