Do Notation – Set 1

First, create an instance of Monad for your Gen newtype, similar to what you did in Set 4. You will also probably want to create an evalGen :: Gen a -> Seed -> a function as well.

With your Monad instance, you should be able to use do syntax. Recall that in Set 1 we had a function called rand :: Seed -> (Integer, Seed). Create a new function makeRandom :: Gen Integer which wraps the rand function inside your new type.

Next, use do syntax to re-create the following function from Set 1:

fiveRands :: Gen [Integer]

To check that you created this function correctly, recall that the product of the five numbers you generate when passing in a seed of mkSeed 1 is 8681089573064486461641871805074254223660.

Once that has been created correctly, create randLetter :: Gen Char and use it to create randString3 :: Gen String, which creates a String of three random characters. If you have an initial seed of 1, when you use this site to calculate the SHA-256 hash of the output of randString3, you get 9d475eb78d3e38085220ed6ebde9d8f7d26540bb1c8f9382479c3acd4c8c94a3.

Lastly, go ahead and create this general function:

generalPair :: Gen a -> Gen b -> Gen (a, b)

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