Thus quoth MarLinn at 15:10 on Wed, Apr 19 2017:
On 2017-04-19 15:58, Joachim Durchholz wrote:
Am 19.04.2017 um 15:13 schrieb Sergiu Ivanov:
However, there are a couple big "backdoors", like the IO monad.
Well, it's so awkward that people don't *want* to use it.
That's partly because IO isn't very well defined, and therefore used as a catch-all. It's like the "other mail" folder, a stuff-drawer in the kitchen or that one room in the basement: random things tend to accumulate and rot in there because they don't have a better place.
Exactly.
One of the worst offenders from my perspective is (non-)determinism.
Oh, right, interesting!
Randomness can be seen as non-deterministic, but it doesn't need IO. At the same time, many things that are in IO are practically not less deterministic than pure functions with _|_ – once you have a good enough model. In other words, these things could be separated. It needs work, to model the real world, to go through all the stuff that's in that black box, to convince people to not use IO if they don't need to, to change the systems to even allow "alternative IOs"… so it's nothing that'll change soon.
I tend to see monads like STM (software transactional memory) and ST (strict state threads) as a kind of "add structure to IO" effort. Also, there's Eff (algebraic effects), but I still haven't had the time to read the seminal work beyond introduction: http://www.eff-lang.org/
IO is the elephant in the room of type-supported hopes of correctness.
I like this image :-) -- Sergiu