FPSE

Assignment 1: OCaml Introduction

In this assignment, you are to write several small programs in OCaml.

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, which you will replace with your code.
  • You may add rec to any function you’d like.
  • You can add any auxiliary functions of your own; put them right before you need to use them.
  • You may reorder functions in any way you like.
• You may also edit assignment1/test/tests.ml which contains some initial tests. These tests are not complete, and you should add more, but you are not required to.
• The file assignment1/src/submission.mli states which functions you are required to have in your submission. You will not submit this file; Gradescope has its own copy. Your submission will not run on Gradescope if you have not defined every function described in assignment1/src/submission.mli.
• There is a assignment1/src/dune and assignment1/test/dune file we set up for you. They 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 because dune automatically builds subdirectories.
  • Also note that running dune test twice in a row will show you no output. It knows that nothing has changed since the previous run, so it skips the tests the second time.
• There is also an assignment1/dune file which just builds a zip of all the files for submission. When you are all done with the homework, perform a final dune build to build the zip. See the submission section below for more on this.

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 OCaml Intro 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 introduction in a somewhat different order than we are doing. They use the Core standard library overlay, so their library functions may look different than yours.
• 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.
• You are 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

• Before you even open any files in VSCode, type dune build from the assignment1/ directory. This will set up the editor to recognize the libraries.
  • If your VSCode editor is not synced across files, run a dune build, and then open the command palette (Ctrl+Shift+P Win or Cmd+Shift+P Mac) and run the OCaml: Restart Language Server command.
• 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 test/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 containing your code so that you can directly use your functions.
• It is up to you which way you prefer, but both have their advantages, and we suggest you do some of each. You are required to have the dune test mode working because we will run those tests when you submit.
• 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, 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 since the last edit.

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 that is 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, but we won’t be enforcing style guidelines yet.
• 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 assignment 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 assignment at least once well ahead of the deadline so that you do not find some problem right at the deadline. We will only look at and grade the most recent submission.