There was an article posted here a while back on how to implement a state machine in Rust, purely using its type system to facilitate state transitions. It's a neat concept, even if it's a bit more verbose than what you'll find in other languages.
How does this compare to the expressivity of Idris' dependent types? I'm intrigued by the idea of type-safe state-machines as e.g. file i/o and network socket code is almost always error-prone. So it feels crucial to rely on the support of a strong type system here.
http://docs.idris-lang.org/en/latest/st/machines.html