anchor.diff:              else
                   Substring.Split.fold separator folder state (substring (str))
   
  -        /// Applies the given function to each of the substrings in the input string that are
  -        /// delimited by elements of a specified Unicode character array, threading an accumulator
  -        /// argument through the computation. The integer index
  -        /// applied to the function is the index of the substring within the virtual array of
  -        /// substrings in the input string. For example, if the newline character (\n) is used
  -        /// as the separator, the index of each substring would be the line number.
  +        /// <summary>
  +        /// Applies the given function to each of the substrings in the input string that are delimited by elements of a specified Unicode
  +        /// character array, threading an accumulator argument through the computation. The integer index applied to the function is the
  +        /// index of the substring within the virtual array of substrings in the input string. For example, if the newline character (\n)
  +        /// is used as the separator, the index of each substring would be the line number.
  +        /// </summary>
  +        /// <param name="separator"></param>
  +        /// <param name="folder"></param>
  +        /// <param name="state"></param>
  +        /// <param name="str"></param>
  +        /// <returns></returns>
           [<CompiledName("FoldIndexed")>]
           let foldi (separator : char[]) (folder : 'State -> int -> substring -> 'State) (state : 'State) (str : string) : 'State =
               // Preconditions
  
positive.code: 
          Substring.tryFindIndex predicate (substring (str))
  
      /// Returns the index of the first character in the string which satisfies the given predicate.
      [<CompiledName("FindIndex")>]
      let findIndex (predicate : char -> bool) (str : string) : int =
          // Preconditions
  
negative.code:             else
                  Substring.Split.iter separator action (substring (str))
  
          /// <summary>
          /// Applies the given function to each of the substrings in the input string that are delimited by elements of a specified
          /// Unicode character array. The integer index applied to the function is the index of the substring within the virtual array
          /// of substrings in the input string. For example, if the newline character (\n) is used as the separator, the index of each
          /// substring would be the line number.
          /// </summary>
          /// <param name="separator"></param>
          /// <param name="action"></param>
          /// <param name="str"></param>
          /// <returns></returns>
          [<CompiledName("IterateIndexed")>]
          let iteri (separator : char[]) (action : int -> substring -> unit) (str : string) : unit =
              // Preconditions
  