6 ms·

> But if you have even a loose criteria for why you pick static typing for a value versus doing the value's verification dynamically, what is that criteria? Th

by tome 9y ago

> But if you have even a loose criteria for why you pick static typing for a value versus doing the value's verification dynamically, what is that criteria? The same as with the choice of anything: what feature to work on this week, whether to automate a process or keep it manual, whether to use JSON or BSON or Protocol Buffers ... It's a judgement call and it's not really possible to give a good answer in a Hacker News comment.

wellpast 9y ago
I agree 100% with this. So if what you're saying here is that in Haskell that this choice is mine, that I can always completely avoid having to choose static verification if I so choose (ie, I can get it a la carte), then that is just plain awesome. Is that what you are saying?
- tome 9y ago
  > I can always completely avoid having to choose static verification if I so choose Well, yes, roughly, of course! You can always choose to use extremely broad types that give minimal guarantees, for example Scientific instead of Double or Int, String instead of MyPreciseErrorType, Map String Dynamic instead of MyPreciseRecordType ... You'll find the Haskell ecosystem is not really designed around that kind of programming because Haskellers don't really like it but it can easily be done, semantically. It will also be a bit awkward syntactically, but it's certainly possible. And then you can opt in to types (a la carte) later by replacing broader types with narrower ones as your project manager refines his specification. But that's not really the point. You can bolt on types to Clojure and you can bolt on dynamism to Haskell. My point is that I've almost always found it better to start in a strongly typed language, even when the requirements are changing rapidly.
  - wellpast 9y ago
    That is an interesting preference. I usually hear it the other way. That people would prefer to start dynamic when they understand the problem/domain the least and then move to static types when they become more sure about the taxonomy of things.
    - bitwalker 9y ago
      For me, fleshing out as much of the types/taxonomy as I can is one of the first things I do before coding towards a solution. Even if the first stab is rough, adjusting the types as knowledge of the domain grows has never been a point of friction for me - most of those changes are incremental, and having the compiler remind me the places I need to update (such as pattern matches) means I don't have to put any mental effort towards that. Even when the changes are significant, I'm still going to have to make basically all the same changes I would have had to make with no type system too. Having the compiler help me out during quick iteration means I can feel comfortable that I'm not forgetting to update areas of the code impacted by changes - when I get to where I want to be, I can be fairly sure I didn't miss anything. That comfort is something I value a lot more highly these days.
      - wellpast 9y ago
        > having the compiler remind me the places I need to update (such as pattern matches) What you're calling a reminder is not just a reminder; it's a requirement -- you are obligated to go update those places in your code before you can deploy/execute the code. Which is the very definition of coupling. This isn't just theoretical. I've encountered this pain again and again in my career. This kind of coupling is severe impedance. Even worse is when the coupling spans teams in an org. It is the difference between pushing a fix or business value out to production now versus having to coordinate across areas of your code base and/or architecture. There is this feeling of control by enforcing every part of your code base play the same game. But when you break out of that, and realize it's a game. That you don't have to design your code such that it has to be updated altogether, then you realize that types are only encouraging you to do this unnecessary thing. You can design very powerful systems with complicated behavior with minimal coupling. Where you get to choose what parts of your code you update at any point in time.
        tome 9y ago
        > You can design very powerful systems with complicated behavior with minimal coupling. It may well be that core.typed and clojure.spec get at least 80% of the benefits of Haskell's type system with no more than 20% of the cost, but in that case Clojurists need to spend their time explaining how rather than railing on Haskell's good parts. (Haskell has plenty of bad parts. The type system is not one of them!)

by tome 9y ago

wellpast 9y ago

I agree 100% with this. So if what you're saying here is that in Haskell that this choice is mine, that I can always completely avoid having to choose static verification if I so choose (ie, I can get it a la carte), then that is just plain awesome. Is that what you are saying?

tome 9y ago
> I can always completely avoid having to choose static verification if I so choose Well, yes, roughly, of course! You can always choose to use extremely broad types that give minimal guarantees, for example Scientific instead of Double or Int, String instead of MyPreciseErrorType, Map String Dynamic instead of MyPreciseRecordType ... You'll find the Haskell ecosystem is not really designed around that kind of programming because Haskellers don't really like it but it can easily be done, semantically. It will also be a bit awkward syntactically, but it's certainly possible. And then you can opt in to types (a la carte) later by replacing broader types with narrower ones as your project manager refines his specification. But that's not really the point. You can bolt on types to Clojure and you can bolt on dynamism to Haskell. My point is that I've almost always found it better to start in a strongly typed language, even when the requirements are changing rapidly.
- wellpast 9y ago
  That is an interesting preference. I usually hear it the other way. That people would prefer to start dynamic when they understand the problem/domain the least and then move to static types when they become more sure about the taxonomy of things.
  - bitwalker 9y ago
    For me, fleshing out as much of the types/taxonomy as I can is one of the first things I do before coding towards a solution. Even if the first stab is rough, adjusting the types as knowledge of the domain grows has never been a point of friction for me - most of those changes are incremental, and having the compiler remind me the places I need to update (such as pattern matches) means I don't have to put any mental effort towards that. Even when the changes are significant, I'm still going to have to make basically all the same changes I would have had to make with no type system too. Having the compiler help me out during quick iteration means I can feel comfortable that I'm not forgetting to update areas of the code impacted by changes - when I get to where I want to be, I can be fairly sure I didn't miss anything. That comfort is something I value a lot more highly these days.
    - wellpast 9y ago
      > having the compiler remind me the places I need to update (such as pattern matches) What you're calling a reminder is not just a reminder; it's a requirement -- you are obligated to go update those places in your code before you can deploy/execute the code. Which is the very definition of coupling. This isn't just theoretical. I've encountered this pain again and again in my career. This kind of coupling is severe impedance. Even worse is when the coupling spans teams in an org. It is the difference between pushing a fix or business value out to production now versus having to coordinate across areas of your code base and/or architecture. There is this feeling of control by enforcing every part of your code base play the same game. But when you break out of that, and realize it's a game. That you don't have to design your code such that it has to be updated altogether, then you realize that types are only encouraging you to do this unnecessary thing. You can design very powerful systems with complicated behavior with minimal coupling. Where you get to choose what parts of your code you update at any point in time.
      - tome 9y ago
        > You can design very powerful systems with complicated behavior with minimal coupling. It may well be that core.typed and clojure.spec get at least 80% of the benefits of Haskell's type system with no more than 20% of the cost, but in that case Clojurists need to spend their time explaining how rather than railing on Haskell's good parts. (Haskell has plenty of bad parts. The type system is not one of them!)