A PDF resume is also available.

Over a decade of experience applying functional programming to hard problems: program analysis, cyber-security, and language design.

Work Experience

Stripe - October 2024 - Present

Infrastructure Engineer - Working on the sorbet typechecker for ruby.

Fastly - May 2022 - October 2024

Principal Engineer - Working on the wasm team, contributing to a variety of projects centered around the running of WebAssembly

• Contributor to wasamtime and the cranelift code generator
• Contributor to the js-compute-sdk, as well as the viceroy local testing environment
• Helped with the implementation and specification of wasi-preview2, and wasi-http
• Participated in the RFC process for wasmtime to help set the direction for debugging

Stripe - April 2019 - May 2022

Infrastructure Engineer - Worked on the sorbet typechecker and compiler for ruby.

• Key contributor on the sorbet compiler, implemented optimizations and improved coverage for the ruby language. Generated native code with llvm, targeting the ruby vm’s c api.
• Implemented type-system features, and improved type-checker runtime performance.
• Mentored an intern on the sorbet compiler project, and organized/ran regular meetings with external contributors from other companies.

groq, inc. Sept 2017 - March 2019

Compiler Engineer - Worked on a compiler for tensorflow models, targeting a custom ASIC that accelerates inference. Focused on compiler performance and optimization of results.

Galois, Inc. - Sept 2007 - Sept 2017

Member of the technical staff - Contributed to a broad range of projects, notably:

• Developed domain specific languages in Haskell, including the msf-haskell metasploit DSL and the ivory DSL for memory-safe embedded programming
• Developed and contributed to multiple full language implementations, including cryptol and the salty GR(1) reactive synthesis DSL
• Implemented the hans network stack
• Aided ASIC design and verification for lightweight cryptographic primitives from Cryptol specifications

CollegeNET, July 2004 - September 2007

Developer - Helped to transition a large desktop application to a suite of web services, and developed tools based off of those web services. Also assisted with some front-end web development, and implemented an LDAP-based authentication system.

CollegeNET, July 2002 - July 2004

Technical Support - Provided technical support to a large client base.

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Education

BS, Computer Science, December 2008

Portland State University, Portland, OR

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Technologies

Languages - haskell, c/c++, ruby, rust, java, javascript, fsharp, ocaml, python, coq, isabelle/hol, shell scripting, assembly (x86, arm)

Tools - git, gnu make, vim/neovim, bazel, z3, smt-lib, gdb, lldb

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Research Projects

• cryptol Maintainer and contributor
  Domain specific language for aiding implementation and verification of cryptographic algorithms.
• ivory Lead engineer
  Haskell EDSL for memory-safe embedded programming.
• salty Lead engineer
  Reactive synthesis DSL for GR(1) specifications.
• msf-haskell Lead engineer
  Haskell EDSL for interacting with the metasploit framework.
• hans Lead engineer
  A TCP/IP network stack implemented in haskell.
• halvm Contributor
  Port of the GHC runtime to the Xen hypervisor.

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Open Source Projects

• sorbet
  The Sorbet typechecker for ruby.
• cereal
  Binary format parsing library
• llvm-pretty
  An EDSL for generating textual llvm bitcode.
• llvm-pretty-bc-parser
  A parser for the llvm binary bitcode format.
• huff
  A fast-forward based classical planning EDSL.
• pretty
  Contributed support for document annotations.

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Publications and Talks

November 2021

Compiling Ruby to Native Code with Sorbet

RubyConf 2021, introducing the Sorbet compiler, and discussing the background of the proect at Stripe. talk

May 2019

Salty-A Domain Specific Language for GR(1) Specifications and Designs

Salty is a domain specific language for GR(1) specifications. It makes it easier to write and debug specifications by adding richer types to the specification language, user-defined macros, specification optimizations, and type-checking. ieee

September 2016

TrackOS: A security-aware real-time operating system, RV.

Introduces the TrackOS embedded operating system. TrackOS allows for run-time monitoring of control flow for running tasks, with a control flow graph that is established during a post-processing pass that doesn’t require access to source code. paper

August 2015

Guilt Free Ivory

Describes the implementation of the Ivory domain specific language in Haskell, as well as the static guarantees that the language provides. paper, talk

December 2014

Multi-App Security Analysis with FUSE

Introduces the FUSE system, which is used to detect collusion between android apps installed on the same phone. paper

November 2014

Programming Languages for High-Assurance Autonomous Vehicles

Introduces domain specific languages as a means for programmer productivity, in the realm of programming for autonomous vehicles. paper

August 2014

Building Embedded Systems with Embedded DSLs, ICFP

An experience report detailing the development of the smaccmpilot autopilot in the Ivory and Tower Haskell EDSLs. At the time, smaccmpilot comprised 10K lines of haskell, and generated about 50K lines of C. paper

September 2010

Concurrent Orchestration in Haskell, Haskell Sympmosium

Describes the embedding of the orc orchestration language as the haskell orc library. acm