Andrew Lelechenko
Director at Barclays
London, England, United Kingdom
Summary
🤩
Rockstar🎓
Top SchoolAndrew Lelechenko is a Director and seasoned Haskell engineer with 12 years of experience and over nine years of commercial work building compilers, DSLs and quantitative analysis tooling for complex financial products. He leads development of a domain-specific language for exotic derivatives at Barclays, translating intricate payoff triggers and pricing models into robust production software. A former number theory researcher with a PhD and 20+ publications on the Riemann zeta-function, he brings deep mathematical rigor to practical engineering problems. Andrew is a prominent open-source maintainer in the Haskell ecosystem—chairing the Core Libraries Committee and contributing to flagship projects like GHC, Cabal, bytestring and aeson. He combines performance-minded engineering (vector, bytestring optimizations) with DevOps and CI modernisation (text, CI migrations), and mentors the next generation through talks and hackathons. Based in London, he pairs academic depth with production-grade delivery across both banking and foundational Haskell infrastructure.
12 years of coding experience
7 years of employment as a software developer
Doctor of Philosophy (Ph.D.) mathematics, Doctor of Philosophy (Ph.D.) mathematics at Odessa I.I.Mechnikov National University
Украинский, Русский, Английский
Github Skills (39)
unit-testing10
json10
github-ci10
benchmark10
lib10
package-management10
testing10
test-framework10
benchmarking10
data-structure10
cicd10
type-system10
compiler-design10
performance-optimization10
build-automation10
Programming languages (20)
Github contributions (5)
haskell/bytestring
May 2020 - Jan 2023
An efficient compact, immutable byte string type (both strict and lazy) suitable for binary or 8-bit character data.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 462 reviews, 201 commits in 2 years 9 months
Contributions summary:Andrew primarily contributed to the development of the Haskell bytestring library. Their contributions included adding and implementing `IsList` instances across different modules, which provides a more convenient way to create bytestrings from list literals. They also worked on various improvements to the library's core functionalities, such as handling `takeWhileEnd`, `dropWhileEnd` and related functions. Further contributions involved the addition of rewrite rules for takeWhile/dropWhile, alongside documentation improvements and refactoring, like the removal of the partial breakByte function.
bytestring
haskell/text
Mar 2021 - Jan 2023
Haskell library for space- and time-efficient operations over Unicode text.
Role in this project:Back-end Developer & DevOps Engineer
Back-end Developer & DevOps EngineerContributions:309 reviews, 175 commits, 209 PRs in 1 year 10 months
Contributions summary:Andrew primarily focused on modernizing and improving the build and testing infrastructure of the Haskell library. They switched the CI/CD pipeline from Travis to GitHub Actions, integrated and updated testing frameworks, and made build system adjustments. Additionally, the user updated dependencies to align with more modern GHC compiler versions and ensured that the benchmarks worked correctly.
haskellunicodestring-manipulationutf8string
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