(* Random -- random number generator *) type generator val newgenseed : real -> generatorval newgen     : unit -> generatorval random     : generator -> realval randomlist : int * generator -> real listval range      : int * int -> generator -> intval rangelist  : int * int -> int * generator -> int list (*    [generator] is the type of random number generators, here the   linear congruential generators from Paulson 1991, 1996.    [newgenseed seed] returns a random number generator with the given seed.    [newgen ()] returns a random number generator, taking the seed from   the system clock.    [random gen] returns a random number in the interval [0..1).    [randomlist (n, gen)] returns a list of n random numbers in the   interval [0,1).    [range (min, max) gen] returns an integral random number in the   range [min, max).  Raises Fail if min > max.    [rangelist (min, max) (n, gen)] returns a list of n integral random   numbers in the range [min, max).  Raises Fail if min > max.  *)