Assignment 1: OCaml Introduction

You are to write several small programs in OCaml. There are five Sections to the homework. In order to help you ease into it we will make two due dates, Part I will be Sections 1-3 and Part II will be Section 4-5. You will submit the whole assignment each time, we just won’t look at Sections 4-5 on the first submission deadline.

The file structure

  • Use the this zip file as the starting point for your assignment. Download and unzip it in a fresh directory/folder that you made (we will suppose you are putting it in a directory assignment1 in the below).
  • 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/ is where you will put your answer code. Currently it has unimplemented () for all the functions, replace that with your code.
  • The only other file you will want to edit is .../assignment1/tests/ which contains some initial tests; these tests are not complete and you should add a few more. Concretely, in the Part II submission we will make sure you added at least 5 tests of your own.
  • 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, unlike make, dune automatically runs builds in subdirectories.
  • When you are all done the homework, from directory .../assignment1 run the command zip -r * or similar to zip up all the files. Please do a dune clean before this so you are submitting only the code, not the binaries.

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 Piazza.
  • 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 Pervasives which are the predefined functions available in OCaml.
    • Note there is one exception to this, Core overrides the comparison operations to 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.
  • You can use Core’s List module functions for the questions we indicate; those functions are generally described under the Base docs which is a subset of Core, here.
  • 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 Piazza.
  • Use Piazza for online help and question clarification. There is also a tool to find teammates on Piazza, feel free to use that to find some coding partners.

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 which runs all of the small suite of tests in the file tests/ 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 ";; which is the same as copy/pasting that file into the top loop as input. Make sure you started utop from the directory in which the file is found for this to work.
  • 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 as well.

Submission and Grading

  • We will be using Gradescope to submit programming assignments. The Gradescope entry code is posted on Piazza.
  • When asked, upload your file which you created as described above.
  • We are going to hand-grade your code so don’t expect a grade to immediately come back from the autograder. It will at least run some sanity checks on it to make sure it is building properly. Note that if dune build and dune test are not working on your own computer it won’t pass our sanity checks, either.
  • If you can’t fix the Gradescope error and/or it makes no sense, post to Piazza 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.