FPSE

Assignment 1: OCaml Introduction

You are to write several small programs in OCaml. There are two Parts to the homework. In order to help you ease into it we will make two due dates for the two Parts. You will submit the whole assignment each time, we just won’t look at Part II on the first submission deadline.

The file structure

• Use this zip file as the starting point for your assignment. Download and unzip it.
• We are starting right off with the standard file structure recommended for projects built with the dune build tool, and you will be using dune to test your program. Please keep this file structure in your coding and submission.
• The file assignment1/src/submission.ml is where you will put your answer code. Currently it has unimplemented () for all the functions, replace that with your code.
  • You may add rec to any function you’d like.
  • You can add any auxilliary functions of your own; put them right before you need to use them.
  • You will not need to modify any code related to the modules; only modify or add functions inside the modules.
• The only other file you will want to edit is assignment1/tests/tests.ml which contains some initial tests; these tests are not complete, and you should add some more. Concretely, in the Part II submission we will make sure you added at least 5 tests of your own. You are not required to add any tests for the Part I submission deadline.
  • These five tests just need to be five non-redundant assert_equal statements.
• There is a assignment1/src/dune and assignment1/tests/dune file we set up for you, they should allow you to run commands dune build and dune test respectively from the top level directory assignment1/ to build and/or test your code. Note you want to stay in the top level to run these commands, dune automatically builds subdirectories.
• There is also an assignment1/dune file which just builds a zip of all the files for submission. When you are all done the homework, perform a final dune build to build the zip.

Resources to help you

Here is a reminder of some resources at your disposal.

• Consult the Course Coding page for information on installing OCaml and getting a good toolchain setup for development.
• Consult the Basic OCaml lecture notes, and if you want to re-watch any lecture they are on Panopto as per the link pinned on Courselore.
• Real World OCaml Chapter 1 is another tutorial introdution in a somewhat different order than we are doing.
• If you are looking for how some standard library function is expressed in OCaml, like not equal, etc, consult the Caml Stdlib which are the predefined functions available in OCaml.
  • Note that Core overrides some of these including the comparison operations which only work on ints. To perform =, < or the like on e.g. floats you need to write Float.(=) 3.2 4.7 for example to check for equality on 3.2 and 4.7, and similarly for < etc. To see what is actually loaded look at the (Core documentation)[https://ocaml.org/p/core/latest/doc/index.html].
• Use Core’s List module functions for the Part II questions we indicate; those functions are generally described under the Core list docs.
• You are strongly encouraged to work with other people on the assignment. You just need to list the names of people you worked with. However remember that you should submit your own write up of the answers. Copying of solutions is not allowed. For the full collaboration policy see here.
• Come to office hours to get help from Prof and CAs. Office hours are posted on Courselore.
• Use Courselore for online help and question clarification.

Coding Methods

• There are two ways you can test your code in OCaml, (1) you can use the top loop (utop) to informally run some tests on it, and (2) you can run the dune test script from directory assignment1/ which runs all of the small suite of tests in the file tests/tests.ml and reports the results.
  • To load all of your functions into the top loop in one go you can use the OCaml top-loop directive #use "src/submission.ml";; which is the same as copy/pasting that file into the top loop as input. Make sure you started utop from the ...assignment1 directory for this to work.
  • alternatively, you can issue the command dune utop which builds and starts utop with your code loaded. Then, type open Submission;; in utop to open up the module Submission comtaining your code so that you can directly use your functions.
• It is up to you which way you prefer working in but both have their advantages and we suggest you do some of each. You are required to have the dune test mode working as that is how we will test your code.
• Note that all dune commands should be run directly from the assignment1/ directory ONLY, dune automatically will also run the build files in any sub-directories by default and so this will run the dune files in src/ and test/ if required. Also note that dune test will implicitly invoke dune build if your code is not compiled yet.

Submission and Grading

• We will be using Gradescope to submit programming assignments. The Gradescope entry code is posted on Courselore.
• Upload your assignment1.zip solutions file built by dune which you will find in assignment1/_build/default/assignment1.zip.
• The Autograder will run the tests we gave you; it will also run additional tests that you might not see (yet). On top of the autograder we will be hand-inspecting your code. We will not be enforcing style guidelines until Assignment 2 however.
• If you can’t fix the Gradescope error and/or it makes no sense, post to Courselore or see someone in office hours.
• You can submit the HW as many times as you want up to the deadline. Any submissions after the deadline will fall under the late submission policy.
• Please submit your draft HW at least once well ahead of the deadline, so you do not find some problem right at the deadline.