Assignment 7: Monads and more functors

In this assignment you will write a functor and a monad module, and then you’ll use the module to refactor some stateful OCaml code to use a state monad.

The file structure

  • Use this zip file for your assignment.
  • Provided are three .mli files src/fpse_monad.mli, src/state_monad.mli, and src/stack_monad.mli. Look at the files in this order, and implement an appropriately named .ml file for each of them.
    • Do not edit the .mli files. You will not submit them.
    • Note you may not use Core in src/fpse_monad.ml. You will not submit a dune file for src/, so you cannot add any libraries to what is in the given dune file.
  • A library using your Stack_monad module is in src/main.ml. See that file and follow the instructions to complete the implementation.
  • There is an empty test/tests.ml in which you will put your tests.
    • You won’t be graded on your tests.
    • You need to fill in the test/dune file to run your tests.
  • Answer a quick discussion question in discussion.txt.

Submission and Grading

  • As usual, run a final dune clean; dune build and then upload _build/default/assignment7.zip to Gradescope.
  • You will be graded with an autograder and on your discussion question.
  • We will check that you actually used the monad in your implementation instead of cheating with mutation.