Justice “JJ” James [pdf]

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

email: work@toki.la
website: toki.la
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, category theory, formal syntax, formal semantics, type-logical grammar, distributed systems, origami
Experienced with: Nim, Rust, Java, Python, Racket, C, Bash, HTML/CSS, Tailwind CSS, Toki Pona
Currently learning: Agda, Haskell, Lean, [Java/Type]Script, Latin, 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

Volunteering

Undergraduate Mathematics Society

May 2023 - Present

President (May 2024 - present): to be determined!
Treasurer (May 2023 - April 2024): handling club logistics, maintaining the clubroom, organizing events

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 [no credit]

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 [no credit]

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 [no credit]

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://toki.la/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 [no credit]

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 [no credit]

Spring 2022

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

Work

Hashbot [Rust]: spam protection for Discord servers

July 2023 - September 2023

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

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 real-world cryptography
Assisted in organization and challenge development for SaplingCTF and MapleCTF

SaplingCTF, MapleCTF, and CursedCTF: cybersecurity competitions

Various dates, 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
CursedCTF 2023: saw over 500 teams and 1,000 participants virtually online from top teams
Additionally hosted both SaplingCTF 2023, MapleCTF 2023, and CursedCTF 2024 to similar success

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 led 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

Relevant 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
...and more!