Fintan Halpenny
Software Programmer at Self-employed
Dublin, Ireland
Summary
🤩
Rockstar🎓
Top SchoolFintan Halpenny is a software programmer with 11 years of experience who applies strong functional programming expertise—particularly in Haskell—to build robust, safe, and efficient platform software. A Trinity College Dublin graduate with first-class honours and a master’s in Computer Science, he contributes to notable open-source projects such as bytestring and dhall-haskell, improving core library safety, performance, and benchmarking. Professionally he’s delivered production systems from the ground up, including Python-based image detection and C-wrapped performance-critical components at LogoGrab, and has experience across C/C++, Rust, and distributed tooling. Equally comfortable exploring new languages and research papers, he pairs practical platform engineering with a continuous-learning mindset and an active side-gig freelance practice in Dublin. Outside work he balances analytical rigor with indoor climbing and kickboxing, which reflect his methodical yet energetic approach to problem solving.
11 years of coding experience
Bachelor of Science (BSc), Integrated Computer Science, First Class Honours, Bachelor of Science (BSc), Integrated Computer Science, First Class Honours at Trinity College, DublinMaster’s Degree, Computer, Master’s Degree, Computer at Trinity College Dublin
Github Skills (20)
benchmark10
testing10
benchmarking10
data-serialization10
distributed-systems10
crdt10
data-structure10
bytestring10
serialization10
performance-optimization10
data-structures10
functional-programming10
rust10
haskell10
command-line-interface9
Programming languages (16)
Github contributions (5)
haskell/bytestring
Dec 2017 - May 2020
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:8 commits, 1 PR, 16 comments in 2 years 5 months
Contributions summary:Fintan primarily contributed to the `bytestring` library by implementing and refining indexing functionalities. Their work included renaming functions, adding new indexing operators, and modifying existing index-related functions across different modules, including lazy and strict versions. They also introduced and tested the `indexMaybe` function, along with corresponding unit tests. This suggests a focus on improving the core functionality and safety of the byte string data structure.
byte-string8-bitbytecompactstring
dhall-lang/dhall-haskell
Jun 2018 - Dec 2018
Maintainable configuration files
Role in this project:Back-end Developer
Back-end DeveloperContributions:12 commits, 22 PRs, 6 pushes in 6 months
Contributions summary:Fintan primarily contributed to the Dhall-Haskell repository by adding benchmarking capabilities and optimizing existing code. They introduced benchmarks for prelude files and issue 108 examples, enhancing the project's performance analysis. Furthermore, the user refactored the code to use strict text for parsing, improved the codebase and documentation, and added profiling capabilities.
configurationghchaskellcabalconfiguration-files
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