anchor.diff:              let! tm'' = body tm'
               let pbod = snd(strip_exists tm'')
               let s, args = strip_comb pbod
  +            // OPTIMIZE : Use pattern-matching here instead of 'length' -- it's faster because length is O(n).
               if name_of s = "_UNGUARDED_PATTERN" && length args = 2 then
                   let! tm1 = rator(hd args)
                   let! tm2 = rator(hd(tl args))                
  
positive.code: (* Character discrimination.                                                 *)
  (* ------------------------------------------------------------------------- *)
  
  // isspace: Tests if a one-character string is some kind of space.
  // issep: Tests if a one-character string is a separator.
  // isbra: Tests if a one-character string is some kind of bracket.
  // issymb: Tests if a one-character string is a symbol other than bracket or separator.
  // isalpha: Tests if a one-character string is alphabetic.
  // isnum: Tests if a one-character string is a decimal digit.
  // isalnum: Tests if a one-character string is alphanumeric.
  let isspace, issep, isbra, issymb, isalpha, isnum, isalnum = 
      let charcode s = Char.code(String.get s 0)
      let spaces = " \t\n\r"
      let separators = ",;"
      let brackets = "()[]{}"
  
negative.code: 
          and print_clauses cls = 
              match cls with
              | [c] ->
                  print_clause c
              | c :: cs -> 
                  print_clause c
                  pp_print_break fmt 1 0
                  pp_print_string fmt "| "
                  print_clauses cs
              | _ ->
                  failwith "print_clauses: Unhandled case."
  
          and print_clause cl = 
              match cl with
              | [p; g; r] -> 
                  print_term 1 p
                  pp_print_string fmt " when "
                  print_term 1 g
                  pp_print_string fmt " -> "
                  print_term 1 r
              | [p; r] -> 
                  print_term 1 p
                  pp_print_string fmt " -> "
                  print_term 1 r
              | _ ->
                  failwith "print_clause: Unhandled case."
  
          fun tm ->
              try
                  print_term 0 tm
              with Failure s as ex ->
                  (* NOTE :   We currently suppress certain exceptions which may be raised during
                              printing; however, we do log them for diagnostics purposes. *)
                  logger.DebugException ("Suppressed exception in 'pp_print_term'.", ex)
  
                  // NOTE: suppress all exceptions in printing
                  ()
  
  