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I'm not arguing that stack frames are as good as manually written error traces can be - they're clearly not. I am simply amazed that people include "generate er

I'm not arguing that stack frames are as good as manually written error traces can be - they're clearly not. I am simply amazed that people include "generate error traces" as a form of "handling" an error. The argument for explicit error values is often something like "it encourages people to actually handle their errors, rather than ignoring them". And on the face of it, this has some merit: we've all seen code that assumes an HTTP request can't fail, and now a small timeout crashes the entire backup procedure or whatever. But if "handle the error" simply means "decorate it with a trace and return it", then exceptions already do this, then you're really admitting that there is no fundamental difference from a exception, because this is exactly what exceptions do, all on their own. Sure, they produce less useful traces, but that's usually a tiny difference. After all, the argument wasn't "you'll get better stack traces than exceptions give you", it was "people will be more careful to handle errors". This is also relevant, because if the goal is to get better error traces, that can also be done with exceptions, with just some small improvements to syntax and semantics (e.g. add syntax for decorating a call site with user supplied context that will get included in any exception bubbled from it; add support in an exception to only print non-library stack frames, add support in the language to declare certain variables as "important" and have them auto-included in stack traces - many ideas).

teeray 1y ago
> there is no fundamental difference from a exception Flow of control is obvious and traceable with explicit errors—they are not some “other” to be dealt with. Exceptions in many languages are gotos, except you don’t know where you are going to and when you might goto. Can this method fail? Who knows! What exceptions can be thrown by this? Impossible to say… better to simply `catch Exception` and be done with it.
- tsimionescu 1y ago
  > Flow of control is obvious and traceable with explicit errors—they are not some “other” to be dealt with. That's a different discussion entirely. And even so, whether any statement can terminate early should not be very relevant: that's why we have try-with-resources/finally/defer and other similar mechanisms. > Exceptions in many languages are gotos, except you don’t know where you are going to and when you might goto. No, they are not, in any language with exceptions except Common Lisp and Windows SEH. Exceptions in all common languages are early returns, they return to the calling function. Of course, if the calling function doesn't catch them, it will also return early to its calling function. Tracing where control flow will continue after an exception is thrown is exactly equivalent to tracing where control flow will continue after an error is returned in Go. > Can this method fail? Who knows! Java has checked exceptions to explicitly mark functions that can throw. While there were some problems with that, especially around the lack of generic exceptions support, this seems like the right way to go, and it mostly got a bad rep simply because of a different zeitgeist in programming at the time. > What exceptions can be thrown by this? Impossible to say… better to simply `catch Exception` and be done with it. This is exactly the same in Go, where every single function returns `error`, and there is very rarely any documentation to say what types of errors it might actually return; and virtually all Go code does "if err != nil", which is exactly the same as catch(Exception). Not to mention that most errors used in most Go code are fmt.Errorf, so they don't carry any type information to begin with.

teeray 1y ago

> there is no fundamental difference from a exception Flow of control is obvious and traceable with explicit errors—they are not some “other” to be dealt with. Exceptions in many languages are gotos, except you don’t know where you are going to and when you might goto. Can this method fail? Who knows! What exceptions can be thrown by this? Impossible to say… better to simply `catch Exception` and be done with it.

tsimionescu 1y ago
> Flow of control is obvious and traceable with explicit errors—they are not some “other” to be dealt with. That's a different discussion entirely. And even so, whether any statement can terminate early should not be very relevant: that's why we have try-with-resources/finally/defer and other similar mechanisms. > Exceptions in many languages are gotos, except you don’t know where you are going to and when you might goto. No, they are not, in any language with exceptions except Common Lisp and Windows SEH. Exceptions in all common languages are early returns, they return to the calling function. Of course, if the calling function doesn't catch them, it will also return early to its calling function. Tracing where control flow will continue after an exception is thrown is exactly equivalent to tracing where control flow will continue after an error is returned in Go. > Can this method fail? Who knows! Java has checked exceptions to explicitly mark functions that can throw. While there were some problems with that, especially around the lack of generic exceptions support, this seems like the right way to go, and it mostly got a bad rep simply because of a different zeitgeist in programming at the time. > What exceptions can be thrown by this? Impossible to say… better to simply `catch Exception` and be done with it. This is exactly the same in Go, where every single function returns `error`, and there is very rarely any documentation to say what types of errors it might actually return; and virtually all Go code does "if err != nil", which is exactly the same as catch(Exception). Not to mention that most errors used in most Go code are fmt.Errorf, so they don't carry any type information to begin with.