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I like exceptions. You can't get away from them, I know Haskell tried, Rust tried, they still have exceptions (perhaps they call them by a different name though

I like exceptions. You can't get away from them, I know Haskell tried, Rust tried, they still have exceptions (perhaps they call them by a different name though). May as well make that system generally available to programers. They also allow you to have the Erlang/Elixir philosophy of happy path coding, "just let it fail", by using a high level exception handler and then just coding the happy path underneath.

byby 3y ago
>I like exceptions. You can't get away from them, I know Haskell tried, Rust tried, they still have exceptions (perhaps they call them by a different name though) Rust has no exceptions in any sense of the word. Exceptions are ways to crash the program in a controlled manner with the ability for these crashes to be caught midway before the program crashes and handled correctly. In rust you can only crash it explicitly using the panic! Macro. No handling. The different name you are looking for is "errors". Rust has errors as do all programs. Some programs have exceptions to handle those errors. Rust does not. If you mean "runtime crashes" then elm is the only language that is popular that uses has no runtime crashes.
- Georgelemental 3y ago
  > Exceptions are ways to crash the program in a controlled manner with the ability for these crashes to be caught midway before the program crashes and handled correctly. > In rust you can only crash it explicitly using the panic! Macro. No handling. You can catch Rust panics with `catch_unwind()` if you compiled your program with `-Cpanic=unwind` (default on most platforms). Under the hood it uses stack unwinding, just like C++ and co's exceptions. But Rust doesn't consider this idiomatic error handling, it's only used in a few special situations (test frameworks, web servers where one buggy session shouldn't take down the process...).
- steveklabnik 3y ago
  I don’t disagree with you that just because rust has a feature similar to exceptions, that it has exceptions, but https://doc.rust-lang.org/std/panic/fn.catch_unwind.html https://doc.rust-lang.org/std/panic/fn.catch_unwind.html does exist.
- Buttons840 3y ago
  You absolutely can catch and handle a panic in Rust [0]. Panics are just exceptions by a different name. Although, I do agree that the Rust ecosystem tries hard to avoid using panics, which is good. [0] Example of catching, handling, and "swallowing" a panic in Rust (GTP4 wrote this): https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=9396dd4cd1714e11e77931faa0ed7638 https://play.rust-lang.org/?version=stable&mode=debug&editio...
  - awestroke 3y ago
    This is very uncommon to do and cannot be compared to exceptions
  - byby 3y ago
    Learned something new. I feel though it's better if most programmers didn't know about this. It looks like cursed knowledge.
    - dmytrish 3y ago
      It's not exactly cursed knowledge, you just have to have enough judgement to understand where it's appropriate. Trying to do magic and patch something on a panic and retry is cursed indeed. If it's about cleaning up resources of a thread and logging this somewhere, then there's nothing cursed about this.
  - sriram_malhar 3y ago
    Catching a panic is _morally_ equivalent to catching a SIGSEGV. It is not meant for normal program error conditions and expected failures (e.g. "No such file").
    - riwsky 3y ago
      I.e. only to be used in exceptional cases.
bedobi 3y ago
The problem is that virtually all languages abuse exceptions and use them for very much expected control flow and business logic. But exceptions should be just that, exceptional. Eg when you make a db call, the db not responding is not exceptional. Nor is not finding the user you're looking for. Those are 100% within the range of expectable outcomes for a db call. fun findUser(userId: String) : Either<Error, User> is MUCH simpler and more powerful than fun findUser(userId: String) //haha, I can actually throw exceptions that aren't in this signature, or return null (wat)
- deleted 3y ago
  [deleted]
kwhitefoot 3y ago
> I like exceptions. You can't get away from them I hope you never program any safety critical machinery. I don't mean exceptions cannot be useful, just that there are circumstances where they are useful and circumstances where they are not.

byby 3y ago

>I like exceptions. You can't get away from them, I know Haskell tried, Rust tried, they still have exceptions (perhaps they call them by a different name though) Rust has no exceptions in any sense of the word. Exceptions are ways to crash the program in a controlled manner with the ability for these crashes to be caught midway before the program crashes and handled correctly. In rust you can only crash it explicitly using the panic! Macro. No handling. The different name you are looking for is "errors". Rust has errors as do all programs. Some programs have exceptions to handle those errors. Rust does not. If you mean "runtime crashes" then elm is the only language that is popular that uses has no runtime crashes.

Georgelemental 3y ago
> Exceptions are ways to crash the program in a controlled manner with the ability for these crashes to be caught midway before the program crashes and handled correctly. > In rust you can only crash it explicitly using the panic! Macro. No handling. You can catch Rust panics with `catch_unwind()` if you compiled your program with `-Cpanic=unwind` (default on most platforms). Under the hood it uses stack unwinding, just like C++ and co's exceptions. But Rust doesn't consider this idiomatic error handling, it's only used in a few special situations (test frameworks, web servers where one buggy session shouldn't take down the process...).
steveklabnik 3y ago
I don’t disagree with you that just because rust has a feature similar to exceptions, that it has exceptions, but https://doc.rust-lang.org/std/panic/fn.catch_unwind.html https://doc.rust-lang.org/std/panic/fn.catch_unwind.html does exist.
Buttons840 3y ago
You absolutely can catch and handle a panic in Rust [0]. Panics are just exceptions by a different name. Although, I do agree that the Rust ecosystem tries hard to avoid using panics, which is good. [0] Example of catching, handling, and "swallowing" a panic in Rust (GTP4 wrote this): https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=9396dd4cd1714e11e77931faa0ed7638 https://play.rust-lang.org/?version=stable&mode=debug&editio...
- awestroke 3y ago
  This is very uncommon to do and cannot be compared to exceptions
- byby 3y ago
  Learned something new. I feel though it's better if most programmers didn't know about this. It looks like cursed knowledge.
  - dmytrish 3y ago
    It's not exactly cursed knowledge, you just have to have enough judgement to understand where it's appropriate. Trying to do magic and patch something on a panic and retry is cursed indeed. If it's about cleaning up resources of a thread and logging this somewhere, then there's nothing cursed about this.
- sriram_malhar 3y ago
  Catching a panic is _morally_ equivalent to catching a SIGSEGV. It is not meant for normal program error conditions and expected failures (e.g. "No such file").
  - riwsky 3y ago
    I.e. only to be used in exceptional cases.

bedobi 3y ago

The problem is that virtually all languages abuse exceptions and use them for very much expected control flow and business logic. But exceptions should be just that, exceptional. Eg when you make a db call, the db not responding is not exceptional. Nor is not finding the user you're looking for. Those are 100% within the range of expectable outcomes for a db call. fun findUser(userId: String) : Either<Error, User> is MUCH simpler and more powerful than fun findUser(userId: String) //haha, I can actually throw exceptions that aren't in this signature, or return null (wat)

deleted 3y ago
[deleted]

kwhitefoot 3y ago

> I like exceptions. You can't get away from them I hope you never program any safety critical machinery. I don't mean exceptions cannot be useful, just that there are circumstances where they are useful and circumstances where they are not.