I'm graduating from college in May. Over my four years working towards my degree, I've taken about forty different courses. As I enter the last month of school, I thought it would be a good time to look back and reflect on the courses that I enjoyed the most. I've picked out five classes, and instead of trying to make any absolute ranking of them, I just decided to present them in the order they were taken, and try and express how each one impacted me.

CIS 240: Introduction to Computer Architecture (Fall 2018)

CIS 240 with C.J. Taylor was my favorite introductory CS class I took at Penn. I came into school with some programming experience, but I was certainly ignorant of the inner workings of how computers took the code I would write, execute it and ultimately give output back to me. 240 started with transistors and logic gates, built up to CMOS circuitry, before jumping the boundary between atoms and bits and introducing us to machine code, assembly, and C for an educational architecture known as LC4. I've heard that pointers in C are a notoriously difficult concept for beginners to grasp, but the evolution up the ladder of abstraction within a computer made C feel like a natural extension of assembly. The course had a very intentional flow to it, and every separate concept felt like it fit into the course well.

Outside of the material, Professor Taylor brought great enthusiasm and a sense of humor to the class. Along with an arsenal of cheesy jokes (my favorite kind) that I'm sure were honed over the semesters lecturing for the course, he came to our midterm exam, which happened to be during the final block of class on the afternoon of Halloween, dressed as Darth Vader, mask and all. He somehow managed to stay in character the entire exam, which I've always respected.

PSCI 232 / COMM 226: Introduction to Political Communication (Fall 2018)

This course was billed to me as one of the most difficult, but also most rewarding, political science courses at Penn. Professor Kathleen Hall Jamieson had been teaching the class since the late 90s, and her expertise shone through. 232 was all about presidential elections, the media, and the electorate. It took a deep dive into presidential campaign advertising in every presidential campaign since Eisenhower's election in 1952. Each week we'd watch campaign ads from a certain campaign, and Professor Jamieson would dig into what made each one persuasive to its audience, or why a given ad flopped.

More important to me than the technicalities of advertising and public communication, we dug into the role that the media itself has in shaping the narrative around elections, and how campaigns can rise or fall in how they take advantage of the media's agenda-setting powers. Jamieson has been an outspoken voice about deception and falsehoods in politics for decades. Standing in 2021, her warnings back then certainly seemed prescient, and the class helped teach me the very active role that social and traditional media play in helping decide how our politics unfolds in the United States.

PSCI 253: International Politics of the Middle East (Fall 2019)

The syllabus was so daunting I almost dropped 253 before the first lecture. Six books in fourteen weeks would add up to roughly two hundred pages of reading each week, and on top of an upperclassman engineering course load, it didn't seem particularly feasible. But after a single lecture with Robert Vitalis, I knew I would stick it through. I feel like it's pretty easy to determine which professors have enjoyed tenure for a good amount of time. While the observation is generally considered to be a nock against a professor's dedication to their teaching responsibilities, I've come to think that there are two distinct sub-types of the "tenured professor" stereotype: there's the stereotypical apathetic professor, but there's also those who take risks with their pedagogy that let you know that they haven't had to justify their teaching methods to a committee for some time. Professor Vitalis brought a particularly wacky attitude to his lectures, often starting class with comments and observations that were intentionally provocative to stir up discussion and disagreement among the class. Even the 200-page weekly readings were, in fact, a teachable moment. Our TA let it slip that Dr. Vitalis's goal was to teach us how to skim effectively in a sort of "baptism by fire."

The books we read in the course also tied into each other in thought-provoking ways. Each dealt with American intervention in the Middle East over the 20th century in a different light. Written assignments were comparative book reviews, a format I haven't heard any other professor using in their classes. The fundamental question of the course, it seemed, was why? Why did the US maintain its interventions on the other side of the world? Why did it present those interventions to the public as it did? We never reached a real answer to any of these questions, but the books brought another lens through which to look at government and the responsibility of those that hold the levers of power in American society, over not just our lives, but the lives of people all over the world.

CIS 341: Compilers and Interpreters (Spring 2020)

I certainly didn't expect 341 to be the class that perfectly capped off my computer science education when I first signed up for it. The course is taught in a bottom-up manner, starting with an assembler for a subset of X86 before moving up to an LLVM to x86 compiler backend. Only after understanding some of the nuances of LLVM does the class move to the frontend of the compiler and deal with lexing, parsing, and types.

Steve Zdancewic expertly connected all the disparate threads of computer science that I'd experienced throughout college and showed how mathematical theory and engineering discipline can be combined to enable the programming languages that developers take for granted today. I don't think there's a better way to explain this than by listing all the topics that 341 touched on, and the other courses that it built on top of:

  • CIS320 (Data Structures and Algorithms): Graph coloring for register allocation

  • CIS262 (Automata, Computability and Complexity): Parsing classes and context-free grammars

  • CIS240: Assembly language and machine code

  • CIS371 (Computer Architecture II): Optimizations around instruction ordering and processor pipelining

I was able to put some knowledge from this course to use right away. Penn Course Review needs to load in a SQL dump of new course reviews every semester. Up until now, we'd relied on loading all the data into a blank MySQL database that we spun up, and then querying it back out in the format we expected. It was a lot of moving parts and generally pretty slow, too. I was able to write a parser that pulled out that same data without having to run it through a full MySQL instance. It just goes to show how the skills that are involved in writing a compiler are useful in their own merits, in addition to being used for compilers.

341 was also where I got exposed to type theory as a subject for the first time, and it sparked my interest in the study of programming languages.

CIS 552: Advanced Programming (Fall 2020)

Stephanie Weirich bills CIS552 as a class that "take[s] good programmers and turn[s] them into excellent ones." It's Penn's only full-credit class taught with Haskell and going into it, I knew next to nothing about the language besides that monads are something people find scary. This might be kind of cliché, but learning Haskell through 552 did change how I thought about programming across the board. Haskell evaluates expressions lazily when they're needed, and not when they're defined. This is an oddity in mainstream languages, but it makes you think more critically about when your code runs. It helped me realize that some expressions in my Python code were being evaluated at their definition when they should have been evaluated lazily.

552 shines in how it introduces monads and explains their usage. Monads aren't not something that clicks for everyone, and they certainly didn't for me right away. We started from the assumptioon that the general definition of monads is too abstract for programming, and the class worked more by example. Through the Maybe monad, State monad, List monad, and a few other examples, the intuition slowly built up for me about how powerful the concept can really be. Haskell's a fundamentally pure functional language that deals only with inputs and outputs to functions. What monads add in this context is a way to abstract out the glue code and plumbing behind a lot of programming patterns in a way that makes code easier to follow and allows Haskell, with a bit of syntactic sugar that the do block provides, to take on some imperative-seeming features that one may find in a more traditional language, like exceptions and global contexts, while maintaining its underlying purity.

The back half of the class was a great tour of what you can do when strong typing is taken to its logical conclusion. I got to work with a friend on a awesome final project, building a typechecker for MongoDB aggregation queries. We were both impressed with the final state of the project, but it's pretty crazy how much type-driven programming helped us out here. We started by defining our abstract syntax tree, and then split up to work on the schema and query parsers and the typechecker itself. Any changes we made in the types were checked by the compiler and we were able to modify our logic, and our monad stack, to add new features without worrying about breaking existing ones.

I don't harbor any notions about how difficult it would be to find a job working with Haskell in industry, but it's certainly a language that I'll continue to play around with going forward. It's got some awesome ideas that are starting to percolate down towards more mainstream languages like Rust.

Wrapping Up

All in all, I consider myself lucky to be able to study things that I find interesting in their own right. Penn's been difficult at times, but it's also afforded me the opportunity to learn from great professors, work on super awesome projects, and meet other students who are extremely driven and passionate about every topic under the sun.

I don't know if there's a single thread that runs through all five of these classes. If I had to pick something, they all certainly had an intentionality to their curriculum. The professors made sure that everything they taught had its place in the larger narrative, helped me understand how each lecture fit into the course topic, and how the course itself fit into the larger field of study. As is pretty apparent from me deciding to write this article, I like finding and understanding patterns – it makes sense that the courses I enjoyed the most were able to weave fabrics out of seemingly disparate threads.

It's certainly cliché to say, but I don't plan on my education stopping after I get my diploma. Who knows if I'll ever go back to school, but I'll take what I've learned about learning itself along with me as I start my career.