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In the absence of enough studies I find it difficult to draw any hard conclusions. I think type systems, such as Haskell’s, strike a good balance between forma

In the absence of enough studies I find it difficult to draw any hard conclusions. I think type systems, such as Haskell’s, strike a good balance between formal and informal specifications such as unit tests or diagrams of boxes and arrows.

pron 7y ago
> In the absence of enough studies I find it difficult to draw any hard conclusions. Me too, which is why I say that it does not seem to make a big positive or negative difference (big differences are easy to find; there haven't been enough studies about the correlation between eating lettuce and baldness so we cannot draw any hard conclusion about there being a correlation or not, and should continue assuming that it's likely not a big cause for baldness nor a definitive cure). > I think type systems, such as Haskell’s, strike a good balance between formal and informal specifications such as unit tests or diagrams of boxes and arrows. I agree. Haskell's type system is OK, and I think most other languages also strike a balance that is roughly equally good, albeit not necessarily through the type system, which is why Haskell doesn't appear to be doing much worse or much better at the bottom line. So I definitely see no good reason to suggest Haskell should lead to drastically lower correctness, and if someone said they cared about correctness and want to use Haskell, I wouldn't think it's an exceptionally bad choice. I think (simple) type systems have many good benefits (code organization, documentation, tooling, AOT-compilation performance), which is why I like them, but correctness just isn't one of them. And why should it be? Theory certainly does not suggest simple types should have a big impact on correctness. The strength of the Haskell type system is such that for most uses of it, for any well-typed Haskell program, there is a very small finite-state program that satisfies the same type (expressible as a very small program), yet clearly most of what the program does -- as well as its code -- lies well beyond its type-equivalent small FSM. So any argument that says that the type would still have a big impact of correctness despite the theory saying it shouldn't would also need to explain why other techniques, like tests without a type system, aren't at least as effective (cost/benefit-wise).
- naasking 7y ago
  > I think (simple) type systems have many good benefits (code organization, documentation, tooling, AOT-compilation performance), which is why I like them, but correctness just isn't one of them Most of those impact correctness (amongst other benefits), otherwise we wouldn't care about them. None of the studies that have been carried out tested the long-term benefits of types, which is precisely where types would shine,so I cannot agree with your conclusions in this thread.
  - pron 7y ago
    > Most of those impact correctness (amongst other benefits), otherwise we wouldn't care about them. Well, it doesn't seem like they do because, again, we can't find significant correctness differences. But I care about them because they improves my subjective experience (enjoyment). I don't know if it's universal, though. I care a great deal about the art I enjoy, but I don't make any universal claims about it improving productivity or something. And I find any such claims -- just like unsubstantiated claims about programming languages -- to be just like claims about homeopathy: I understand and sympathize with the psychological mechanism that causes people to make them, but they are unlikely to have any large real-world validity. > None of the studies that have been carried out tested the long-term benefits of types, which is precisely where types would shine, so I cannot agree with your conclusions in this thread. It's not a "conclusion." Until we find evidence that lettuce cures baldness -- or causes it -- we assume it doesn't. But it's even stronger than that. We don't need difficult studies to detect large effects. Large effects are often found even without studies at all. If eating lettuce increased or decreased baldness by 50%, we would have noticed. Especially in software, which is a huge economic undertaking and therefore has powerful selective pressures, adaptive techniques have very clear adoption dynamics, of the kind we've seen with unit testing and even garbage collection. Yet we don't quite see them with Haskell. Haskell doesn't even spread rapidly inside organizations that already use it. On the other hand, it doesn't rapidly disappear, either, as we'd expect from a highly maladaptive practice. Its dynamics is similar to that of a neutral trait. So the scientific reality is that Haskell in all likelihood does not have a large negative or positive effect on any important bottom-line metric, at least until proven otherwise. This is the current working assumption, and it's great news for Haskell fans: Haskell is probably a reasonable choice, and not significantly worse than others. Looks like the FDA would call consider it a safe nutritional supplement.

pron 7y ago

> In the absence of enough studies I find it difficult to draw any hard conclusions. Me too, which is why I say that it does not seem to make a big positive or negative difference (big differences are easy to find; there haven't been enough studies about the correlation between eating lettuce and baldness so we cannot draw any hard conclusion about there being a correlation or not, and should continue assuming that it's likely not a big cause for baldness nor a definitive cure). > I think type systems, such as Haskell’s, strike a good balance between formal and informal specifications such as unit tests or diagrams of boxes and arrows. I agree. Haskell's type system is OK, and I think most other languages also strike a balance that is roughly equally good, albeit not necessarily through the type system, which is why Haskell doesn't appear to be doing much worse or much better at the bottom line. So I definitely see no good reason to suggest Haskell should lead to drastically lower correctness, and if someone said they cared about correctness and want to use Haskell, I wouldn't think it's an exceptionally bad choice. I think (simple) type systems have many good benefits (code organization, documentation, tooling, AOT-compilation performance), which is why I like them, but correctness just isn't one of them. And why should it be? Theory certainly does not suggest simple types should have a big impact on correctness. The strength of the Haskell type system is such that for most uses of it, for any well-typed Haskell program, there is a very small finite-state program that satisfies the same type (expressible as a very small program), yet clearly most of what the program does -- as well as its code -- lies well beyond its type-equivalent small FSM. So any argument that says that the type would still have a big impact of correctness despite the theory saying it shouldn't would also need to explain why other techniques, like tests without a type system, aren't at least as effective (cost/benefit-wise).

naasking 7y ago
> I think (simple) type systems have many good benefits (code organization, documentation, tooling, AOT-compilation performance), which is why I like them, but correctness just isn't one of them Most of those impact correctness (amongst other benefits), otherwise we wouldn't care about them. None of the studies that have been carried out tested the long-term benefits of types, which is precisely where types would shine,so I cannot agree with your conclusions in this thread.
- pron 7y ago
  > Most of those impact correctness (amongst other benefits), otherwise we wouldn't care about them. Well, it doesn't seem like they do because, again, we can't find significant correctness differences. But I care about them because they improves my subjective experience (enjoyment). I don't know if it's universal, though. I care a great deal about the art I enjoy, but I don't make any universal claims about it improving productivity or something. And I find any such claims -- just like unsubstantiated claims about programming languages -- to be just like claims about homeopathy: I understand and sympathize with the psychological mechanism that causes people to make them, but they are unlikely to have any large real-world validity. > None of the studies that have been carried out tested the long-term benefits of types, which is precisely where types would shine, so I cannot agree with your conclusions in this thread. It's not a "conclusion." Until we find evidence that lettuce cures baldness -- or causes it -- we assume it doesn't. But it's even stronger than that. We don't need difficult studies to detect large effects. Large effects are often found even without studies at all. If eating lettuce increased or decreased baldness by 50%, we would have noticed. Especially in software, which is a huge economic undertaking and therefore has powerful selective pressures, adaptive techniques have very clear adoption dynamics, of the kind we've seen with unit testing and even garbage collection. Yet we don't quite see them with Haskell. Haskell doesn't even spread rapidly inside organizations that already use it. On the other hand, it doesn't rapidly disappear, either, as we'd expect from a highly maladaptive practice. Its dynamics is similar to that of a neutral trait. So the scientific reality is that Haskell in all likelihood does not have a large negative or positive effect on any important bottom-line metric, at least until proven otherwise. This is the current working assumption, and it's great news for Haskell fans: Haskell is probably a reasonable choice, and not significantly worse than others. Looks like the FDA would call consider it a safe nutritional supplement.