John Ericson
Software Engineer at Obsidian Systems LLC
New York, New York, United States
Summary
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Rockstar🎓
Top SchoolJohn Ericson is a software engineer with 14 years of experience based in New York, specializing in back-end systems, build tooling, and compiler/runtime work. He contributes to high-profile open-source projects such as LLVM, GHC, Cargo, Nix, and Meson, frequently improving build infrastructure, dependency management, and cross-platform integration. His background in Haskell-heavy ecosystems (reflex, cabal, clash) and hands-on work untangling build environments shows a strong affinity for correctness, maintainability, and reproducible builds. At Obsidian Systems he applies this expertise to production engineering problems, and earlier internships at Galois reinforced his focus on robust CI and build systems. He also holds a BS in Mathematics and Computer Science from Brown and an MA in Economics, a combination that informs both rigorous technical design and pragmatic trade-off analysis. Notably, he favors simplifying designs by removing restrictions that create feature bloat, crafting cleaner foundations rather than piling on functionality.
14 years of coding experience
Master of Arts - MA, Economics, Master of Arts - MA, Economics at John Jay College (CUNY)Bachelor of Science - BS, Mathematics and Computer Science, Bachelor of Science - BS, Mathematics and Computer Science at Brown University
Stackoverflow
133reputation
979reached
5answers
1question
Github Skills (74)
structures10
dependency-management10
verilog10
obelisk10
package-management10
python10
nix10
testing10
openbsd10
vhdl10
monad-transformers10
language-design10
build-automation10
elf10
backend10
Programming languages (31)
Github contributions (5)
reflex-frp/reflex-platform
Jun 2015 - Jul 2022
A curated package set and set of tools that let you build Haskell packages so they can run on a variety of platforms. reflex-platform is built on top of the nix package manager.
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:8 releases, 15 reviews, 833 commits in 7 years 1 month
Contributions summary:John primarily worked on integrating and adapting the jsaddle library within the reflex-platform project. This included converting existing code, like portions of jsaddle and related components, to the cabal2nix build system, suggesting expertise with Haskell and the Nix package manager. The user also addressed problems encountered during the build process for iOS and other targets.
reflex-frppackage-setghcjsfunctional-reactive-programminghaskell
reflex-frp/reflex
Sep 2017 - Jun 2022
Interactive programs without callbacks or side-effects. Functional Reactive Programming (FRP) uses composable events and time-varying values to describe interactive systems as pure functions. Just like other pure functional code, functional reactive code is easier to get right on the first try, maintain, and reuse.
Role in this project:Back-end Developer
Back-end DeveloperContributions:1 release, 3 reviews, 160 commits in 4 years 9 months
Contributions summary:John primarily focused on refactoring and improving the core functions of the Reflex FRP library. They made significant changes to the `Reflex.Class` module, deprecating and renaming functions to steer users towards more performant and correct implementations of reactive programming patterns. Further contributions involved fixing typos and adjusting several core functions, and adding and implementing functions to enhance the overall library.
eventsreflex-frpdescribecallbacksfunctional-reactive-programming
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