Interesting! This seems to be in very early development. I do not fully understamd the simple example, but somehow the basic idea and delarative nature feels promising to me. I do not have a good enough understanding of this. I fear that a single central declaration of all the tasks and communication channels might get unwieldy for a system with realistic complexity.

The landing page is a bit disappointing in that regard. I'd rather see example programs for listening on a socket or setting up a piped parent/child pair than computing Fibonacci numbers. I guess the fib_loop example at least demonstrates that mutable state is readily accessible (not what you'd necessarily expect in a Haskell eDSL), but I think for a domain-specific language it would be better salesmanship to demonstrate a domain-related task.