CS 421: Programming Languages and Compilers
Machine Problems for Fall 2013
Topic: Issued: Due at 21:59pm CT on: Automatic extension
(with 20% penalty)
until 21:59pm CT on:
MP1 OCaml: Basic OCaml Tuesday, Aug 27 Tuesday, Sep 3 Thursday, Sep 5
MP2 Pattern Matching and Recursion Tuesday, Sep 3 Tuesday, Sep 10 Thursday, Sep 12
MP3 Recursion Patterns and Higher-Order Functions Tuesday, Sep 10 Thursday, Sep 19 Saturday, Sep 21
MP4 Continuation-Passing Style Tuesesday, Sep 17 Wednesday, Sep 25 Friday, Sep 27
MP5 Working with ADTs: Implementing CPS Tuesday, Sep 24 Tuesday, Oct 1 Thursday, Oct 3
MP6 A Unification-Based Type Inferencer Tuesday, Oct 1 Thursday, Oct 17 Saturday, Oct 19
MP7 Unification Algorithm Tuesday, Oct 15 Tuesday, Oct 22 Thursday, Oct 24
MP8 A Lexer for MicroML Tuesday, Oct 22 Tuesday, Oct 29 Thursday, Oct 31
MP9 A Parser for MicroML Tuesday, Oct 29 Thursday, Nov 7 Saturday, Nov 9
MP10 An Evaluator for MicroML Sunday, Nov 10 Thursday, Nov 21 Saturday, Nov 23
MP11 A Transition Semantics Evaluator for CPS Wednesday, Nov 27 Thursday, Dec 5 Saturday, Dec 7

Hand Written Assignments for Fall 2013
Topic: Issued: Due at 19:59pm CT on: Automatic extension
(with 20% penalty)
until 19:59pm CT on:
HW1 Evaluation and Evironments Tuesday, Aug 27 Tuesday, Sep 3 Thursday, Sep 5
HW2 Evaluating the application of a function Tuesday, Sep 3 Tuesday, Sep 10 Thursday, Sep 12
HW3 Order of Evaluation Wednesday, Sep 11 Thursday, Sep 19 Saturday, Sep 21
HW4 CSP Transformation; Working with Mathematical Specifications Wednesday, Sep 18 Wednesday, Sep 25 Friday, Sep 27
HW5 Algebraic Datatypes Tuesday, Sep 24 Tuesday, Oct 1 Thursday, Oct 3
HW6 Polymorphic Type Inference Tuesday, Oct 1 Tuesday, Oct 15 Thursday, Oct 17
HW7 Unification Tuesday, Oct 15 Tuesday, Oct 22 Thursday, Oct 24
HW8 Regular Expressions Wednesday, Oct 23 Tuesday, Oct 29 Thursday, Oct 31
HW9 Parse Trees, Ambiguous Grammars, LR and Recursive Descent Parsing Tuesday, Oct 29 Thursday, Nov 7 Saturday, Nov 9
HW10 Operational and Transition Semantics Saturday, Nov 9 Thursday, Nov 21 Saturday, Nov 23
HW11 Lambda Calculus Thursday, Nov 21 Thursday, Dec 5 Saturday, Dec 7

Note: The late penaly is 20% of the total number of points possible on the base part of the assignment, plus 20% of the total points possible on the extra credit, if you attempt the extra credit. It is not 20% of the number of points your earn.

Instructions for Submitting Assignments
  • Each student is given an svn directory that needs to be checked out once before it can be used for submission as follows:
    mkdir <working_directory>
    svn co https://subversion.ews.illinois.edu/svn/fa13-cs421/<your_netid> <working_directory>
  • After the initial checkout, <working_directory> will contain a subdirectory assignments. Once an assignment (mp or hw) has been announced, if you do an
    svn up
    you will add a directory named after the assignment (e.g. mp1) in the assignments directory. That directory will contain the information posted on the web for that assignment.
  • For an hw, the directory will contain the file hwX.pdf, whereX is the number of the hw. You need to add to that directory your solution, which needs to be called as specified in the distributed file hwX.pdf. Typically, your submission will need to be called hwX-solution.pdf, but check the assignment's instructions.
  • For an mp, for submission you will need to place the specified file(s) in the top-level of the mpX directory. You may find it most convenient to unpack the mpXgrader.tar.gz directory and then cd mpXgrader; mv * .. to put the files for building the grader in the top level of the mpX directory. This way you will be able to leave the files you must submit in place while testing them. Please try to avoid committing the files from mpXgrader.tar.gz into the svn repository; it only occupies unnecessary space on the server and wastes unnecessary network traffic.
  • To submit an assignment, once you have completed the necessry files as decribed in the assignment instructions, in the assignment directory
    svn add <solution file>
    svn commit -m "<your comment here>"
    You may restrict svn commit to a specific collection of files and directories by adding a list to the end of the command.
  • You may do multiple commits; the version that is in the repository at the time specified by the assignment instructions on the due date is that one that will be collected and graded.
Guide for Doing MPs
A guide for how to attack an MP:
  1. Download mpXgrader.tar.gz and untar it (tar xzf mpXgrader.tar.gz where X is the number of the MP). This will create an mpXgrader directory. Go into that directory.
  2. Copy the mpX-skeleton.ml file as mpX.ml. To make sure you have all the necessary pieces, start by executing make. This will create the grader executable. Run the executable (./grader). Examine the failing test cases for places where errors produced by your code. At this point, everything should compile, but the score will be 0.
  3. Read and understand the problem for the handout that you wish to begin working on. (Usually, working from top to bottom makes most sense.) There is a tests file in this directory. This is an important file containing the an incomplete set of test cases; you'll want to add more cases to test your code more thoroughly. Reread the problem from the handout, examining any sample output given. Open the tests file in the mpXgrader directory. Find the test cases given for that problem. Add your own test cases by following the same pattern as of the existing test cases. Try to get a good coverage of your function's behaviour. You should even try to have enough cases to guarantee that you will catch any errors. (This is not always possible, but a desirable goal.) And yes, test cases should be written even before starting the implementation of your function. This is a good software development practice.
  4. If necessary, reread the statement of the problem once more. Place your code for the solution in mpX.ml (or mpX.mll or mpX.mly as specified by the assignment instructions) replacing the stub found there for it. Implement your function. Try to do this in a step-wise fashion. When you think you have a solution (or enough of a part of one to compile and be worth testing), save you work and execute make and the ./grader again. Examine the passing and failing test cases again. Each failure is an instance where your code failed to give the right output for the given input, and you will need to examine your code to figure out why. When you are finished making a round of corrections, run make, followed by ./grader again. Continue until you find no more errors.
  5. When your code no longer generates any errors for the problem on which you were working, return to steps 3) and 4) to proceed with the next problem you wish to solve, until there are no more problems to be solved.
  6. When you have finished all problems (or given up and left the problem with the version given in the skeleton file), you will need to copy your solution file to an EWS Linux machine, if it is not already there. Once it is on an EWS Linux machine, you need to run the handin program on it. Please refer to the FAQ handin instructions for details.
    Note: While handin is non-functional, submission shall be by svn as described above.
Interactive Debugging
In addition to running "make" and "grader", you probably want to test your code interactively at the top level:
  1. Enter the directory with your source file.
  2. Type ocaml at the command line.
  3. Type #load "mpXcommon.cmo";; at the OCaml prompt, where X is the number of the assignment (this loads in the common stuff that we give you in compiled form by default).
  4. Type #use "mpX.ml";; at the OCaml prompt, where X is the number of the assignment. This loads in your code, and adds the functions you have defined to the identifiers recognized at top level.
  5. Type in commands followed by ';;' at the OCaml prompt to test your code interactively. Anything that you can do in a code file, you can do interactively. For example, you can define identifiers using 'let x = ...', etc...
  6. With each MP, you will be given a solution in compiled form. You may interactively test the solution to a problem, after having loaded "mpXcommon.cmo", by loading the solution file by typing #load "solution.cmo";;. After that, if you are supposed to write a function called, say splat, and wish to fine out what it does on an input, say 39.2, you make execute the solution's version of splat by typing Solution.splat 39.2;;. Notice the capitalization.