CS223 Homework 6
Due Friday, 5/21/2010


1. [25] Prove monad rules are satisfied.
Do the Exercise at the end of script18.txt that involves 
proving that the three example monads satisfy the monad
laws.

2. [30] Output version of Input module in SML.
Write an Output structure that defines output analogues
of the types and functions in the structure Input
(file input.sml).  Also write an output version of
the additional functionality provided by InputParsing.
Finally, define an output version of the natList 
reader action that outputs a list of natural numbers.

3. [20] Translate Input to Haskell
Translate the definitions in Input and InputParsing
into Haskell. Can you define generic versions analagous
to the InputFn functor in inputfn.sml?

4. [25] Haskell Input using the IO monad.
Modify your Haskell definitions from Problem 3 to use
the built-in IO monad instead of the reader monad.