Import the hashing function with the following line:

import Data.Hashable

Test the hash function on a string as follows; this function is actually a wrapper around the hashWithSalt function with a default salt value:

main = do
  print $ hash "foo" 

Test out the hashWithSalt functions using different initial salt values as follows:

  print $ hashWithSalt 1 "foo"
  print $ hashWithSalt 2 "foo"

We can also hash tuples and lists as follows:

  print $ hash [ (1 :: Int, "hello", True)
               , (0 :: Int, "goodbye", False) ]

Notice in the following output how the first three hashes produce different results even though their input is the same:

$ runhaskell Main.hs

7207853227093559468
367897294438771247
687941543139326482
6768682186886785615