These are some of the open-source programming projects I am, or have been, working on. All projects listed below, and many more, are available at my GitHub profile page.
The goal of Hyper is to make use of row polymorphism, and other tasty type system features in PureScript, to enforce correctly stacked middleware in HTTP server applications. All effects of middleware should be reflected in the types to ensure that otherwise common mistakes cannot be made. This is one of my most recent projects. Please have a look at the the documentation for more information.
PureScript Spec is a testing framework for PureScript, which I have maintained since April, 2015. It is inspired by the Haskell testing frame hspec, and supports synchronous and asynchronous tests using a simple DSL, interoperability with other testing tools, and test output in various formats.
The Oden Programming Language
As described at oden-lang.github.io, Oden is an experimental, statically typed, functional programming language, built for the Go ecosystem. I worked on the language for the majority of 2016, rounding off in October. Why I stopped working on Oden is explained in greater detail in the blog post Taking a Step Back from Oden. The compiler is written in Haskell, and I am very satisified with the readability of the source code, and the correctness of the compiler. I hope that the source code can be of use, or serve as inspiration, to others.
During my work at Sony Mobile, I created DataFlow, a tool that renders graphs using a declarative markup. It is built around the DFD format, but also supports sequence diagrams and structured data output. We used it to document our service integrations and security requirements between separate systems, and integrated it in to our bigger documentation workflow. The software is written in Haskell and has seen very few bugs.