Andres Löh is a Partner at Well-Typed LLP and a veteran Haskell engineer with over 20 years of hands-on experience and 21 years in the field, combining consultancy, development and training for commercial projects. His work sits at the intersection of language design and practical tooling—specialising in datatype-generic programming, type systems, dependent types and embedded DSLs—and he has substantial academic experience from a PhD and faculty roles. Andres is a prolific open-source contributor to cornerstone Haskell projects such as Cabal, Servant, cabal2nix and Liquid Haskell, improving build systems, parsers and server routing with a focus on robustness and maintainability. He has a track record of pushing compiler and tooling support (including UHC support in Cabal) and applying research ideas to production-grade infrastructure. Based in Regensburg, Germany, he founded community initiatives like the Dutch Haskell Users Group and an annual Applied Functional Programming summer school, demonstrating both technical depth and community leadership. His background in mathematics and computer science informs a rigorous, design-oriented approach to modular, reusable software.
21 years of coding experience
3 years of employment as a software developer
Diplom Mathematics Computer Science, Diplom Mathematics Computer Science at University of Konstanz
PhD Computer Science, PhD Computer Science at Utrecht University
Official upstream development repository for Cabal and cabal-install
Role in this project:
Back-end Developer
Contributions:342 commits, 16 PRs, 14 pushes in 11 years
Contributions summary:Andres contributed significantly to the Cabal project, focusing on enhancing the build process and supporting additional compilers such as UHC. Their work includes implementing new functions within the build information structure, and addressing bugs related to file paths and dependency handling within different compiler backends. The user also added a new module for UHC compiler support, which included building, configuring, installing, and registering package features within the cabal-install environment.
Servant is a Haskell DSL for describing, serving, querying, mocking, documenting web applications and more!
Role in this project:
Back-end Developer
Contributions:23 commits, 12 PRs, 14 pushes in 1 year 7 months
Contributions summary:Andres made significant contributions to the `servant` library, focusing on enhancing its server-side implementation. They introduced a new `Router` datatype for more efficient server interpretation, reducing routing complexity. The user also addressed error handling, test cases, and the implementation of API combinators such as authorization. The changes demonstrate a deep understanding of Haskell and web application server design principles.
web-applicationsservingqueryinghaskelldsl
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