regression/conv.sml

   1 val big: IntInf.int = 0x80000000
   2
   3 fun try (barg: IntInf.int): unit =
   4        let val small = SOME (IntInf.toInt barg)
   5                   handle Overflow => NONE
   6            val bstr = IntInf.toString barg
   7            fun fail msg = print ("Fail " ^ msg ^ ": " ^ bstr ^ "\n")
   8            val isSmall = ~ big <= barg andalso barg < big
   9        in case small of
  10              NONE => if isSmall
  11                         then fail "1"
  12                         else ()
  13              | SOME sarg => if isSmall
  14                                then let val sstr = Int.toString sarg
  15                                     in if bstr = sstr
  16                                        andalso barg = IntInf.fromInt sarg
  17                                           then ()
  18                                           else fail "2"
  19                                     end
  20                                else fail "3"
  21        end
  22
  23 fun spin (low: IntInf.int, limit: IntInf.int): unit =
  24        let fun loop (arg: IntInf.int): unit =
  25                   if arg = limit
  26                      then ()
  27                      else (
  28                         try arg;
  29                         try (~ arg);
  30                         loop (arg + 1)
  31                      )
  32        in loop low
  33        end
  34
  35 val _ = spin (0, 1000)
  36 val _ = spin (big - 1000, big + 1000)
  37
  38 val _ = print "All ok\n"