Justice “JJ” James [pdf]

I like general mathematics, [programming/_] language theory, and Taylor Swift.

email: work@toki.la
website: apropos.codes
github: omentic
linkedin: ~jj

Education

University of British Columbia September 2021 - April 2025 [expected]

Year: 3rd | Major: Mathematics | Minor: Linguistics

Skills & Interests

Interests: type theory, computer security, compiler engineering, abstract algebra, language design
Experienced with: Nim, Rust, Java, Agda, Python, Racket, C, Bash, HTML/CSS, Tailwind CSS, Toki Pona
Currently learning: Haskell, [Java/Type]Script, Lean, Latin, category theory, type theory, cryptography
Assorted skills: Linux, Git, server administration, HAProxy, Nginx, Docker, cross-site scripting, SQL injection, template injection, request smuggling, CSRF, reverse engineering, digital forensics analysis

Work & Volunteering

Hashbot [Rust]: spam protection for Discord servers

July 2023 - October 2023

Worked on transitioning an image matching service across databases for better decoupling & scalability
Freelance contract work

ICFP 2023: International Conference for Functional Programming

September 2023

Student volunteer and attendee

PLDI 2023: Programming Language Design & Implementation Conference

June 2023

Virtual student volunteer

Relevant Coursework

CPSC 539b: Dependent Types

Fall 2023 (current)

Working through Dan Friedman's and David Thrane Christiansen's The Little Typer
Working through David Thrane Christiansen's Checking Dependent Types by Normalization by Evaluation
Working on implementing a dependent type checker by normalization by evaluation

CPSC 539b: Implementing Type Systems

Spring 2023

Worked through and discussed Benjamin C. Pierce's Types and Programming Languages
Discussed a bevy of additional papers: primarily Jana Dunsfield's work on bidirectional typechecking
Implemented a type system in Rust as a term project, with bidirectional typechecking, subtyping, and algebraic data types, later extended with typeclasses

CPSC 421: Introduction to the Theory of Computing

Fall 2022

Finite Automata, Pushdown Automata, Turing Machines, Context-Free Grammars, Reductions, Recognizability, Decidability, Computability Theory, Complexity Theory, Complexity Theory
Course notes typeset and available virtually on my website: https://apropos.codes/notes/cpsc421/
Wrote a Turing machine emulator and a hand-rolled Fibonacci program (for fun and for an art piece)
Wrote a Wang tile implementation of a Fibonacci program (also for fun and for an art piece)

CPSC 311 Reading Group: Introduction to Interpreters

Fall 2022

Taken as a replacement for an interpreters course (cancelled by departmental scheduling)
Weekly group meetings ~~nerd club~~, discussing and working through Shriram Krishnamurthi's
Programming Languages: Application and Interpretation (second edition)

CPSC 411: Introduction to Compiler Construction

Spring 2022

Lectures only. Did not attempt assignments. Plan to properly take Spring 2025. (scheduling... :-< )

Experience

Maple Bacon: a competitive cybersecurity Capture the Flag (CTF) team

September 2021 - Present

#1 team in Canada, peaking at #7 worldwide in May 2022 (ending the year at #25 worldwide)
Executive (September 2022 - present): creating challenges and running meetings and handling logistics
Won DEF CON CTF 30 and 31 alongside CMU and Theori.io (as the Maple Mallard Magistrates)
Specializing in miscellaneous security-related problems, reverse engineering compiled binary code, and modern web exploitation, with an interest in learning cryptography and binary exploitation
Assisted in organization and challenge development for SaplingCTF and MapleCTF

SaplingCTF and MapleCTF: cybersecurity competitions

February & September 2022 & 2023

Co-coordinator: helped in handling logistics and assisted in development of educational challenges
SaplingCTF 2022: saw over 75 teams and 175 participants locally from the University of British Columbia
MapleCTF 2022: saw over 600 teams and 1,500 participants virtually online from across the globe
Additionally hosted both SaplingCTF 2023 and MapleCTF 2023 to similar success

CursedCTF: a satirical (but actual) CTF competition

April 2023

Wrote a number of challenges, carefully crafted the website experience, and assisted in organization
Ran incredibly successfully, with over 550 teams & active participants and a CTFTime rating of 23.33/25

UBC Bionics: engineering design team building a bionic arm

September 2021 - June 2022

Architected an asynchronous Rust framework to bridge statistical models in Python and kernel code
Designed around various I/O, threading, Python, and hardware limitations

Spartronics 4915: a high-school FIRST robotics team

September 2017 - June 2021

Programmer (September 2017 - June 2021), Leadership Member (June 2018 - June 2021)
Programming Lead (June 2019 - June 2021), Team Captain (June 2019 - June 2021)
Designed and lead the implementation of a modular command-based robot codebase
Worked closely with experienced industry mentors to facilitate student learning and student-mentor connections through pair programming, code review, and an educational curriculum

Projects

apus [Java] and bamboo [Nim]: a pair of web browsers from scratch

Entirely from-scratch implementations: only rely on the standard Sockets API for network access
Implements HTML parsing (HTML LS), URI handling (RFC 3986), partial HTTP 1.0 support (RFC 1945)
Custom layout engine + renderer with support for basic CSS: built on Swing [Java] and Pixie [Nim]

chrysanthemum [Rust]: a simple language with a complex type system

Models and interprets the simply typed lambda calculus through Rust's algebraic data types
Checks and infers types bidirectionally: with support for extensive subtyping and typeclasses
Support for a broad variety of types: bools, nats, ints, floats, chars, strings, structs, enums, functions

nim-uxn [Nim]: a macro-full implementation of an abstract stack machine

Implemented the core VM of Uxn, an aesthetic minimalistic computing stack, in a custom DSL
Future plans to implement I/O and package as both a library and an emulator

athena [Java]: a modular codebase for a competitive FIRST Robotics Competition robot

Designed the codebase to be approachable as an introduction to programming as a whole
Command-based architecture separates code into owned, self-contained modules

additional projects

advent-of-code [Various]: aesthetic and efficient solutions to yearly programming puzzles
dictionarium [Rust]: a speedy, offline, command-line dictionary program
viceverba [JavaScript]: a minimal port of the Latin learning app Vice Verba to the web
...and more!