anchor.diff:                  let toks, rst1 = tokens rst
                   t :: toks, rst1
           with Noparse ->
  +            // Noparse exception ends lexing
               [], i
       fst << (tokens .>>. many(some isspace) .>>. finished |>> (fst << fst))
   
  
positive.code:     let undertail = stringof(a "_") .>>. possibly simple_ident |>> collect
      let ident = (undertail <|> simple_ident) .>>. many undertail |>> collect
      let septok = stringof(some issep)
      let escapecode i = 
          match i with
          | "\\" :: rst -> "\\", rst
  
negative.code: 
  /// Lexically analyze an input string.
  let lex = 
      // collect - collects result of parser into a string, i.e. (string * string list -> string)
      let collect(h, t) = end_itlist (+) (h :: t)
      let reserve = 
          function 
  