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The common data structures in pure languages are slightly different than what you would find in a stateful language, so you do need to take care to make it so o

The common data structures in pure languages are slightly different than what you would find in a stateful language, so you do need to take care to make it so only via what data structures you choose to use. Additionally, the author does say they use Control.ST, which depending how you look at it is either a pure wrapper over stateful operations or stateful looking syntax implemented with technically pure semantics. https://www.microsoft.com/en-us/research/wp-content/uploads/1994/06/lazy-functional-state-threads.pdf https://www.microsoft.com/en-us/research/wp-content/uploads/... The main loop is probably a tail recursive function.

dwohnitmok 7y ago
That's not the correct link. Idris' ST is not the same as Haskell's ST. Haskell's ST is a way of introducing locally scoped mutability, which is indistinguishable from immutability to an outside observer, but can offer better performance. Idris' ST is a way of implementing a state machine with statically checked state transitions. http://docs.idris-lang.org/en/latest/st/state.html http://docs.idris-lang.org/en/latest/st/state.html