Load File: __scramble.sml

   This module illustrates some of the lower level binary IO features provided
   by the basis library.  It defines functions to scramble and unscramble
   files into a different order.  It demonstrates the BinIO structure,
   in particular the underlying functional streams used in the BinIO.StreamIO
   structure.  It also demonstrates the use of the BinPrimIO, Position and
   Word8Array structures.

   The functions Scramble.scramble and Scramble.unscramble open an
   in-file and an out-file, convert them into their underlying functional
   streams and either scramble or unscramble them using the given 
   permutation function. Examples of such functions are provided by this 
   module as the functions Scramble.rotate, which takes an integer argument
   and rotates to the right by that number of bytes, Scramble.reverse,
   which reverses elements, and Scramble.shuffle

   For example

	Scramble.scramble (Scramble.reverse) ("foo","foo.s");
      
   reverses the order of the file `foo' and writes the result to `foo.s', 
   while 

        Scramble.scramble (Scramble.shuffle) ("foo","foo.s");
 
   performs a shuffle operation on the order of elements in the file,
   ard

        Scramble.unscramble (Scramble.shuffle) ("foo.s","foo");
 
   unscrambles a file scrambled using Scramble.shuffle, and so on.