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CSCI 3155 - Fall 2022

Course Overview and Goals

This course is about principles, concepts, and ideas that underlie programming languages. But what does this statement mean?

As a student of computer science, it is completely reasonable to think and ask, “Why bother? I’m proficient and like programming in Ruby. Isn’t that enough? Isn’t language choice just a matter of taste? If not, should I be using another language?”

Certainly, there are social factors and an aspect of personal preference that affect the programming languages that we use. But there is also a body of principles and mathematical theories that allow us to discuss and think about languages in a rigorous manner. We study these underpinnings because a language affects the way one approaches problems working in that language and affects the way one implements that language. At the end of this course, we hope that you will have grown in the following ways:

  • You will be able to learn new languages quickly and select a suitable one for your task.
  • You will gain new ways of viewing computation and approaching algorithmic problems.
  • You will gain new ways of viewing programs.
  • You will gain insight into avoiding mistakes for when you design languages.

We will dissect programming languages by constructing interpreters. The semester project is to construct an interpreter for JavaScript (incrementally). We will see that interpreters are the basis for realizing computation, and we will study the programming language theory that enable us to reason carefully about a language’s design and implementation. Our approach will be gradual in that we will initially consider a small subset of JavaScript and then slowly grow the aspects of the language that we consider.

Incoming students often expect this course to be what I will call a trip to the Zoo of Programming Languages. While it is certainly interesting to go to the zoo, we seek a more informative and scientific study of the underlying principles. A more apt analogy is an anatomy course where we will study the “guts” and inner-workings of programming languages. After this course, such an anatomical study will enable us to compare and contrast programming languages in a substantive manner and address the learning goals outlined above.

The course covers many aspects of using, understanding, and reasoning about programming languages (e.g., syntax, scoping, induction, data types, and typing). We will build up a set of mathematical tools for careful discourse. A significant part is devoted to abstraction, that is, how languages help programming in the large (e.g., subtyping polymorphism, parametric polymorphism, modules, and objects).

This course prepares you for introductory courses on both programming language implementation (e.g., CSCI 4555) and programming language semantics (e.g., CSCI 5535).

Prerequisites

The prerequisites for this course are CSCI 2270 (Computer Science 2: Data Structures) and CSCI 2824 (Discrete Mathematics). It is also suggested that one of CSCI 2400 (Computer Systems) or ECEN 2120 (Computers as Components) be either previously taken or be taken in the same semester.

If you have not already taken these courses or if you have any concerns, please talk with the instructor. Proficiency in programming is absolutely expected, though there is no specific language required. This means that you should be able to pick up a new programming language with relative ease. You will be expected to learn new programming languages with guidance but relatively independently in this course.

Requirements

The course consists of the following learning activities:

  • Lab Assignments (30%). This course is a project-based course, so most of the understanding will come from attacking the lab assignments. Lab assignments will be two weeks in length with an intermediate checkpoint. Because iteration on lab assignments is the basis for learning in this course, we offer a generous “redo” policy on lab assignments (see below). No late assignments will be accepted, but your lowest lab grade will be dropped.
  • Exercises (10%). There will be in-class, online, and checkpoint exercises associated with each unit. There will be no make-ups if you miss an in-class exercise, but your lowest exercise grade will be dropped.
  • Class Participation (5%). Participation includes both in-class and online discussion. See below for expectations for class participation.
  • Reading. There will be required articles or book chapters to read. This course will emphasize learning from the resources out of class and actively discussing problems and questions in class.

And the following summative assessments:

  • Midterm Exam (25%). There will be one midterm exam.
  • Final Exam (30%).

Grading. Your overall grade will be determined using the ratio for lab assignments, exercises, class participation, the midterm exam, and the final exam shown above. There is no predetermined curve (i.e., I hope everyone gets an A based on the level of mastery demonstrated). Cutoffs will be announced after the midterm exam to give you an idea where you stand.

Regrades. Any concern about an error in grading must be submitted within one week of when it is returned. Any coursework submitted for reconsideration may be regraded in its entirety, which could result in a lower score if warranted. To request a regrade, please go to the Course Manager’s office hours with your coursework and an explanation of what you believe the grading error to be.

Make-Up Exam Policy. There will be no special or make-up examinations for any student (except in the case of emergency or the stated religious observances).

Redo Policy. This course is project-based, which means the learning is driven primarily by the lab assignments. To encourage iteration until mastery, you may “redo” any assignment via an oral interview with an instructor for a maximum of 90%. In a “redo interview,” the instructor is probing for your level of understanding and may ask different questions than you have seen previously. A “redo” must be completed within one week of when the assignment is returned. You may request one interview per assignment. However, you may discuss your solutions with the instructors in office hours as much as you like before requesting your regrade. You must submit your lab on time to participate in a “redo”. To request a “redo” interview, please contact the Course Manager to schedule a time with a “redo” interviewer from the Instructional Staff (i.e., either an Instructor or a TA).

Extra Credit and Participation. Extra credit opportunities may be offered during the course semester. Extra credit is recorded separately from normal grades and are only considered after final grades have been calculated. If your final grade is just below a grade cutoff, extra credit may bump you up to the next grade. Finding a bug in the course materials that is then adopted is a standing offer for extra credit.

Teams and Pair Programming. Your goal as a team is to help each other successfully complete the course project and the course together. You are asked to work on lab assignments in pairs from your team, enabling pair programming. You are also asked to work with a different partner for each lab assignment, enabling the benefit from the experience of your team. You will get your partner in your lab section in the week before the lab is released. Lab assignments are the main opportunity to learn material in this course and thus they count for a relatively small portion of your final grade. It is strongly advised that you work on all the problems in a lab assignment together so that you understand all of the material and are prepared for the exam. Everyone will submit assignments, and you must cite your partner explicitly. You are responsible for all assignments individually (e.g., if your partner drops the course midway though an assignment, you still need to submit on time).

Autotesting and Checkpoints. We will use automated testing as way to provide you with quick, iterative feedback on your progress in achieving the learning outcomes. Automated testing will be used minimally for evaluation but will be used as a checkpoint for interview grading.

Interview Grading. The primary feedback mechanism for your lab assignments will be through an interview with a Reviewer. The interviews will be conducted individually. Please be on time to your interview slot. Given the large number of students, we cannot offer make up interviews if you miss it nor extra time if you are late.

Workload. CSCI 3155 is a 4-credit course. This translates to the standard expectation of approximately 8 hours of outside of class time per week or 16 hours per two-week lab.

Evaluation

Both your ideas and also the clarity with which they are expressed matter—both in your English prose and your code!

We will consider the following criteria in our grading:

  • How well does your submission answer the questions? For example, a common mistake is to give an example when a question asks for an explanation. An example may be useful in your explanation, but it should not take the place of the explanation.
  • How clear is your submission? If we cannot understand what you are trying to say, then we cannot give you points for it. Try reading your answer aloud to yourself or a friend; this technique is often a great way to identify holes in your reasoning. For code, not every program that “works” deserves full credit. We must be able to read and understand your intent. Make sure you state any preconditions or invariants for your functions (either in comments, as assertions, or as require clauses as appropriate).

Expectations for Class Participation

Classes focus on discussion, so it is certainly important to participate in class and read the readings beforehand.

Students are expected to be active participants in class and in the online forums (e.g., around at least 1 substantive post per week). You may and are encouraged to post comments or questions about the reading before the class where we will cover it. Posting early will help focus our discussion.

Here are some examples of good comments:

  • Questions about the reading or the class discussion.
  • Thoughtful answers to other people’s questions.
  • Clarification of some point discussed in class.
  • Thoughtful comments on a web resource related to a reading or class discussion that caught your attention (e.g., you happened upon an interesting blog post related to our discussion). Note that simply giving a link is not considered a thoughtful comment.

If everything from a class meeting seems clear to you, try to come up with a question that tests your classmates’ understanding. Put yourself in the position of an instructor!

Overall, the intent is for you to to take a moment to reflect upon the day’s reading or class discussion. The course staff will read all posts but may not respond to all of them (e.g., if we believe your classmates’ answers are sufficient).

Textbook and Resources

Textbook. The primary reading for the course is the course notes: Principles and Practice in Programming Languages.

The course follows some ideas from a supplemental text: Essentials of Programming Languages, 3rd edition by Daniel P. Friedman and Mitchell Wand. We will take liberty to deviate this text where appropriate, as we will use a different implementation language (Scala instead of Scheme). This book is available as an e-book to all University students.

Prof. Sankaranarayanan has authored a set of course notes following the design of this course but using a different pedagogical style.

We also strongly recommend that you get access to Programming in Scala, 4th edition by Martin Odersky, Lex Spoon, and Bill Venners. This book is an extended tutorial for learning Scala by those directly involved in the language’s development. This book is available as an e-book to all University students.

Two other useful Scala texts: Atomic Scala by Bruce Eckel and Dianne Marsh; and Functional Programming in Scala by Paul Chiusano and Runar Bjarnason.

JavaScript.

Scala.

  • Language Website. The central point for Scala information. The reference implementation for this course is Scala 2.13.x.
  • Metals for VS Code. You are welcome to use any code development environment, but the course staff will only support Metals for VS Code.ntelliJ. There are many options, including IntelliJ IDEA, Emacs, Eclipse, and NetBeans.
  • Scala Style Guide. We will in general follow the Scala style guide.

Git. There are many guides and tutorials on using git and GitHub. Here are some links to start with:

Tools

Canvas. We will use Canvas for grades and feedback. You should have been automatically enrolled. If you know of someone that does not have the necessary Canvas access, please direct them to the Course Manager to resolve the matter.

Piazza. We will be using Piazza for online, outside-of-class discussion. Rather than emailing questions to the course staff, questions should be posted on Piazza. I encourage you to make class-wide posts whenever possible, but there is an option to send an instructor-private message.

Computing. We strongly suggest you use a Unix-based development environment (e.g., Ubuntu Linux, macOS). While not officially supported, we will try to help with other Scala installs. Please feel free to ask for help on the forum and help by contributing your experience.

Integrity of the Course Materials

The development effort in the course materials, including the lab assignments, the exercises, and the exams, is significant. You agree that you will not share any course materials publicly or privately outside of your teams. The course materials, include your or anyone else’s solutions to the lab assignments, exercises, and exams. In particular, you agree not to post your solutions to the lab assignments in a public source code repository, such as public GitHub repositories. Use the private source code repositories provided to you for your work.

Note that there is no conflict with the Collaboration Policy described below. You are welcome and encouraged to support each other in the learning of the material.

Collaboration Policy

You are welcome and encouraged to work together in learning the material. If you worked with someone on an assignment, or if your submission includes quotes from a book, a paper, or a web site, you should thank the source. Bottom line, feel free to use resources that are available to you as long as the use is reasonable and you cite them in your submission. However, copying answers directly or indirectly from solution manuals, web pages, or your peers is certainly unreasonable. If you have any doubts in this regard, please ask the course staff.

Academic Dishonesty Policy. We will go by the Honor Code set forth by the University. Academic sanctions may include, but is not limited to, a zero for the assignment or a failing grade for the course.

Classroom Norms

We trust and expect everyone to behave in a civil and courteous manner.

In class, the course staff promises their undivided attention and reciprocally expects the same from you. In today’s world, this promise requires turning off transmitting devices, such as mobile phones and wi-fi on notebook computers. The use of notebook computers should be discussed with the instructor and they should be used only for purposes directly relevant to the class discussion. Please notify the course staff if you encounter behavior that distracts from your learning.

Classroom Behavior

We will also go by the policies set forth by the University:

Both students and faculty are responsible for maintaining an appropriate learning environment in all instructional settings, whether in person, remote or online. Those who fail to adhere to such behavioral standards may be subject to discipline. Professional courtesy and sensitivity are especially important with respect to individuals and topics dealing with race, color, national origin, sex, pregnancy, age, disability, creed, religion, sexual orientation, gender identity, gender expression, veteran status, political affiliation or political philosophy. For more information, see the classroom behavior policy, the Student Code of Conduct, and the Office of Institutional Equity and Compliance.

Requirements for COVID-19

We will go by the policies set forth by the University:

As a matter of public health and safety, all members of the CU Boulder community and all visitors to campus must follow university, department and building requirements and all public health orders in place to reduce the risk of spreading infectious disease. CU Boulder currently requires COVID-19 vaccination and boosters for all faculty, staff and students. Students, faculty and staff must upload proof of vaccination and boosters or file for an exemption based on medical, ethical or moral grounds through the MyCUHealth portal.

The CU Boulder campus is currently mask-optional. However, if public health conditions change and masks are again required in classrooms, students who fail to adhere to masking requirements will be asked to leave class, and students who do not leave class when asked or who refuse to comply with these requirements will be referred to Student Conduct and Conflict Resolution. For more information, see the policy on classroom behavior and the Student Code of Conduct. If you require accommodation because a disability prevents you from fulfilling these safety measures, please follow the steps in the “Accommodation for Disabilities” statement on this syllabus.

If you feel ill and think you might have COVID-19, if you have tested positive for COVID-19, or if you are unvaccinated or partially vaccinated and have been in close contact with someone who has COVID-19, you should stay home and follow the further guidance of the Public Health Office (contacttracing@colorado.edu). If you are fully vaccinated and have been in close contact with someone who has COVID-19, you do not need to stay home; rather, you should self-monitor for symptoms and follow the further guidance of the Public Health Office (contacttracing@colorado.edu).

Accommodations for Disabilities

We will also go by the policies set forth by the University:

If you qualify for accommodations because of a disability, please submit to your professor a letter from Disability Services in a timely manner so that your needs can be addressed. Disability Services determines accommodations based on documented disabilities. Information on requesting accommodations is located on the Disability Services website. Contact Disability Services at 303-492-8671 or dsinfo@colorado.edu for further assistance. If you have a temporary medical condition, see Temporary Medical Conditions on the Disability Services website.

Preferred Student Names and Pronouns

We will also go by the policies set forth by the University:

CU Boulder recognizes that students’ legal information doesn’t always align with how they identify. Students may update their preferred names and pronouns via the student portal; those preferred names and pronouns are listed on instructors’ class rosters. In the absence of such updates, the name that appears on the class roster is the student’s legal name.

Honor Code

We will also go by the policies set forth by the University:

All students enrolled in a University of Colorado Boulder course are responsible for knowing and adhering to the Honor Code. Violations of the Honor Code may include, but are not limited to: plagiarism, cheating, fabrication, lying, bribery, threat, unauthorized access to academic materials, clicker fraud, submitting the same or similar work in more than one course without permission from all course instructors involved, and aiding academic dishonesty. All incidents of academic misconduct will be reported to Student Conduct & Conflict Resolution (honor@colorado.edu); 303-492-5550). Students found responsible for violating the Honor Code will be assigned resolution outcomes from the Student Conduct & Conflict Resolution as well as be subject to academic sanctions from the faculty member. Additional information regarding the Honor Code academic integrity policy can be found on the Honor Code website.

Sexual Misconduct, Discrimination, Harassment and/or Related Retaliation

We will go by the policies set forth by the University:

CU Boulder is committed to fostering an inclusive and welcoming learning, working, and living environment. University policy prohibits sexual misconduct (harassment, exploitation, and assault), intimate partner violence (dating or domestic violence), stalking, protected-class discrimination and harassment, and related retaliation by or against members of our community on- and off-campus. These behaviors harm individuals and our community. The Office of Institutional Equity and Compliance (OIEC) addresses these policies, and individuals who believe they have been subjected to misconduct can contact OIEC at 303-492-2127 or email cureport@colorado.edu. Information about university policies, reporting options, and support resources can be found on the OIEC website.

Please know that faculty and graduate instructors have a responsibility to inform OIEC when they are made aware of any issues related to these policies regardless of when or where they occurred to ensure that individuals impacted receive information about their rights, support resources, and resolution options. To learn more about reporting and support options for a variety of concerns, visit Don’t Ignore It.

Religious Observances

We will go by the policies set forth by the University:

Campus policy regarding religious observances requires that faculty make every effort to deal reasonably and fairly with all students who, because of religious obligations, have conflicts with scheduled exams, assignments or required attendance.

See the campus policy regarding religious observances for full details.

We will try to accommodate religious conflicts in a reasonable manner. Please check the exam dates and submit all requests for adjustments within the first four weeks of class. To discuss a special accommodation, please contact the Course Manager with your request.

Acknowledgments

This course has benefited from the organization and experience from prior versions of this class taught by Sriram Sankaranarayanan, Gowtham Kaki, Tom Nelson, Jim Baker, and Amer Diwan.