The Rich Hickey talk gets way better if you frame it as closed vs. open world instead of static vs. dynamic.
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Yeah, very little of it seems to actually be about static vs dynamic. It's mostly just a quick way for him to set up what he';s actually interested in talking about, which is closed vs open
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I mean it comes down to Haskell having invariant function types, right? Replacing `a -> Maybe a` with `Maybe a -> a` is a classic example of "weakening precondition, strengthening postcondition" in design-by-contract
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Yeah, it shows up in simple subtyping too (if you want to do it soundly)