Language Of Purpose 1266 words drafted on December 25, 2020.

I believe language is how we come to understand the world we live in. While the student adopts the languages of their teachers, we must impose our language directly upon machines which are constructed from matter found on Earth. These programming languages, in theory, provide us the machine interface to command unquestionably; bound only by feasibility and creativity. Given this immense world-building power, it is important to decide what aspects we want in the language, what cases we wish to avoid, and what properties are unavoidable. These natural consequences of programming language design are fascinating to me. In particular, I have become intrigued by the concept of the reference, much as how I felt enlightened by the function itself. Taming references allows a programming language with mutation to act more like a purely functional language and gives the programmer more control. One thread I would like to follow in my research is how substructural type systems can be weaved together with other interesting concepts. I have decided to pursue a research path so I can explore ideas with others who share similar visions and who will challenge me along the way.

To help guide my research I have come up with a few very high level questions which should give rise to more specific hypotheses for study. I do not expect to receive a direct answer to these questions, but I hope they help keep me on the right path.

More concrete questions should motivate my research. For example, would the shell programming environment be substantially improved by the ability to embed other programming languages inline? Are there valid metrics for assessing the gain from this approach over the existing methods for calling external programs? And perhaps most interestingly, what design patterns become more naturally expressed in this context?

One project I wish to continue working on over the years is my shell, oursh, which aims to address some of these questions, as well as remain POSIX compatible. The high level idea is somewhat simple, by adding “shebang blocks”, the programmer can write arbitrary languages inline, just as they would write any other expression. I have worked on many other projects, between school projects, personal projects, professional projects, and open source projects. Some are simply playgrounds for exploring, while others are critical tools. Alacritty, the open source terminal emulator I am writing this document with, is an example of something critical I use on a daily basis and contribute to from time to time. I have also written a number of parsers and small languages. So many problems are more concretely understood in the frame of parsing and serialization, since exhaustive case analysis can be done and ambiguity can be detected. I believe this makes for much more reliable systems in practice.

My background is currently somewhat mixed between research and industrial working experience. Between the three, semester-long co-op/internships during my undergraduate education and the few years of work afterwards, I have around 5 years under my belt. During my junior year and after graduation, I moved to the San Francisco bay area to work for Apple. I was on a small team within the iPhone hardware team whose job it was to write supporting software tools for project management, development and evaluation of the hardware. One of my tasks was to write what amounted to an ORM for Radar (Apple’s bug management service), which was rewarding since it allowed me to replace a massive amount of ad-hoc code with a cohesive library. There were some very exciting parts of my job, but I was becoming quickly drained by the inability to talk with people about my work and the general culture of secrecy. I had always planned on going back to graduate school, so I decided I needed start looking for my way into academia. This led me back to Boston and Northeastern University.

For the last year or so I have been working at the intersection of Security and Programming Languages at Northeastern, developing a novel language for Multiparty Computation (MPC). This project started under IARPA’s HECTOR program, but has continued with our own focus on designing a language with explicit information flow between parties and secure conditional evaluation. While working on this project, I had to balance both research questions and mandated deliverables, some of which were not directly relevant to our research. Despite the fact that the term “multiparty computation” could mean a variety of things, it has somewhat specific meaning in the security community and I had to learn to speak their language. This was especially critical since we are designing a programming language to assist with the kind of work they do. One of our central contributions is the notion of a virtual party, which simulates a trusted third party who can perform computations on data themselves. Of course, as the name implies, the virtual party doesn’t actually exist, and the compiler generates the corresponding program for the real parties. By modeling a language with explicit participants of computation and allowing them to compose shared virtual participants themselves, we can encode a wide class of programs such as recursively defined protocols, and hybrid programs. The concept of a virtual party, implemented with sound cryptography, gives an appealing way to express programs without free access to information. The task of keeping a system operating without complete knowledge becomes significantly harder. There will always be a risk of program failure, and there may not be a single right answer to many questions of design. Still, we should strive for making systems both secure and accessible where possible and on giving tools to programmers for controlling access to their user’s data. What I mean by accessibility is roughly the following:

Perhaps accessibility simply means technology should “just work”. In order to achieve that we must all agree on our definitions, just as a conversation without the need for a dictionary feels more natural. Having personally discussed, debated, argued, and come to terms in both academia and industry alike, I have seen how much energy this can take. The ability to check our own understanding before attempting to interface with each other is often a crucial step in the process. I see this as analogous to the static type checking of many programming languages. These types give us the ability to restrict our thoughts to what matters and focus on making things work.

Reflecting back on some of my guiding questions, there seems to still be a chasm between where we are today and where I would like to be. I would like to see a world where building secure applications is easy enough that users themselves can trust their own devices again. Not everyone is going to be a security expert and not everyone is even going to understand the first thing about our languages. It is the average developer, however, looking to make something for their constituents who I would like to see empowered to protect user’s integrity. To accomplish this, I see no other way than for an effort to be made in industry based on solid foundations I hope to help develop with my research one day.