In a previous posts we examined the current state of GUI programming in Haskell, how imperative libraries get in the way of functional beauty, and how (non-FRP) reactive programming enables short, declarative code and facilitates code reuse. But without the low-level details, without more information on how this framework is structured, all we have is an idea, a draft on a piece of paper. It’s impossible to know how much effort it will require, or how much it will affect our code. ...

Some time ago I tried to create big programs with user interfaces in Haskell and found that none of the FRP frameworks worked as expected. Some were incomplete, others didn’t compile, and efficiency was an issue in those that did work. ...