Here comes June's meetup talks.
1. Gergő Érdi: Compositional type checking
The venerable Hindley-Milner type system can sometimes lead to misleading type error messages because, as we'll see, it imposes an ordering on type constraints that is not rooted in the structure of the user's program.
A compositional type system is one where typing judgements are local, i.e. only using the typing judgements of immediate subexpressions. I'll explain a particular compositional type system that agrees with HM on well-typed expressions, and show a practical implementation for a small model language.
2. Paul Meng: Writing Atom plugin with GHCJS
This is the second in the Haskell editor mini-hacking series. Following the last month's Neovim session, it is to encourage the new-comer to start hacking on Haskell with the editor you use daily. And this month we are going to hack on Atom. Most of the Atom haskell plugins are written in Coffeescript, we would see what would happen if we write them by GHCJS.