random_source()
      

let rs = random_source()
let ri = random_source_for_integers(rs)
let rr = random_source_for_reals(rs) 
let ra = random_source_for_byte_arrays(rs)

ri(10)
//  ...a random integer..

rr()
//  ...a random real...

ra(10)
//  #u8[...array of 10 random bytes...]