This recipe shows how to build a "guess the random number" game using a custom AppM monad via the ReaderT design pattern and Aff, storing the game state in a mutable variable via a Ref.
Example output:
Guess the random number. It's between 1 and 10. You have 5 guesses. Enter 'q' to quit. Invalid inputs will not count against you.
Prevous guesses: []
Guess a number between 1 - 10: al
'al' is not an integer. Try again (Use 'q' to quit).
Prevous guesses: []
Guess a number between 1 - 10: 52.9
'52.9' is not an integer. Try again (Use 'q' to quit).
Prevous guesses: []
Guess a number between 1 - 10: 52
52 was not between 1 and 10. Try again.
Prevous guesses: []
Guess a number between 1 - 10: 5
Prevous guesses: [5]
Guess a number between 1 - 10: 2
Prevous guesses: [5,2]
Guess a number between 1 - 10: 4
Prevous guesses: [5,2,4]
Guess a number between 1 - 10: 3
Prevous guesses: [5,2,4,3]
Guess a number between 1 - 10: 5
You already guessed 5 previously. Please guess a different number.
Prevous guesses: [5,2,4,3]
Guess a number between 1 - 10: 0
0 was not between 1 and 10. Try again.
Prevous guesses: [5,2,4,3]
Guess a number between 1 - 10: 9
Player lost! The answer was 6
Guesses made: [5,2,4,3,9]