Oleg Grenrus
Haskell Consultant at Well-Typed LLP
Pori, Satakunta, Finland
Summary
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Rockstar🎓
Top SchoolOleg Grenrus is a Haskell consultant with 17 years of professional software experience, based in Pori, Finland, currently at Well-Typed LLP. He has deep backend expertise in Haskell and compiler/tooling internals, contributing to prominent projects like GHC, Aeson, Servant, Cabal, and the Haskell Tool Stack. His open-source work spans libraries for containers, parsing, JSON, testing and FRP, showing a knack for type-class design, build/CI improvements and cross-package compatibility. Prior roles include full-stack and mobile work at Futurice and academic teaching at Aalto University, reflecting both applied engineering and mentoring experience. Notably, he has made low-level contributions to compiler generics and diagnostics, indicating a strong grasp of language design as well as practical API maintenance.
17 years of coding experience
13 years of employment as a software developer
Master's degree, Electrical Engineering, Master's degree, Electrical Engineering at Aalto University
Russian, Finnish, English
Stackoverflow
12,067reputation
496kreached
206answers
18questions
scala
top-5%
logic
top-5%
haskell
top-5%
Github Skills (92)
dependency-management10
agda10
package-management10
parser-combinators10
testing10
language-design10
template-haskell10
build-automation10
backend10
haskell10
javascript10
typeclass10
purescript10
clojure10
hackage10
Programming languages (33)
Github contributions (5)
haskell/parsec
Sep 2015 - Jan 2023
A monadic parser combinator library
Role in this project:
Backend Developer
Backend DeveloperContributions:10 reviews, 35 commits, 53 PRs in 7 years 4 months
Contributions summary:Oleg primarily focused on maintaining and updating the Parsec library, a monadic parser combinator library written in Haskell. Their contributions included bumping upper bounds for dependencies like HUnit and semigroups, fixing compatibility issues, and adding new features. Furthermore, the user integrated GitHub Actions for the project's CI/CD pipeline, improved the build process, and added new test cases. They also introduced and improved some parsing functions and fixed the code style.
combinatorparser
haskell-servant/servant
Feb 2016 - Mar 2020
Servant is a Haskell DSL for describing, serving, querying, mocking, documenting web applications and more!
Role in this project:Back-end Developer
Back-end DeveloperContributions:590 commits, 439 PRs, 381 pushes in 4 years 1 month
Contributions summary:Oleg primarily contributed to enhancing the servant library. Their work included implementing a new rst link syntax in documentation, adding GHC compiler options to multiple cabal files, and integrating new test suites. They also focused on refining build configurations by adding new upper bounds and dependencies, and improving the integration of test cases and doctests.
dslhaskellmocking
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