7 ms·

The standard library's error package supporting chaining errors would be a start. The standard library's error package recording call stacks as this one does.

by TheDong 10y ago

The standard library's error package supporting chaining errors would be a start. The standard library's error package recording call stacks as this one does. The standard library's error package supporting more rich information than just a string, but having both a message, a parent error (recursive data structure), a code-location (package / file / line number), and structured metadata available. Rich tooling as rust has in the form of Either + macros to make it easy to do the right thing(tm) ... And I know most people won't like this, but exceptions would also solve this. Note all the above suggestions are viable without exceptions, but exceptions are a fine solution in their own right. This really is just an area the standard library is utterly deficient in (much like logging), and the lack of macros, generics, and sum types makes elegant error handling much more difficult.

jimjimjim 10y ago
I believe there are many languages that you could use that would have all of these features. That way you would have a language that would be more appropriate to your programming style without needing to add extra features to Go that possibly don't fit with Go's language style. (Note: post edited to remove snark.)
- catnaroek 10y ago
  I don't see how `panic` and `recover` are any simpler than exceptions. Could you explain? P.D.: The downvote didn't come from me.
  - jimjimjim 10y ago
    Well, they are kind of more difficult than exceptions, but I think that's the point. Handling errors by use of an exception mechanism is discouraged in idiomatic go. A big part of the style and simplicity comes from not needing to worry about what possible exceptions could come bubbling up from a library stack and under what conditions. Even though people complain about the repetition of "if err !=nil" at least you know from the function declaration if an error is could occur.
    - catnaroek 10y ago
      FWIW, I don't have anything against checking errors - I agree that it's preferable to exceptions, but the way it happens to be done in Go is rather distasteful. A sum type, as suggested by TheDong, would make things clearer, by statically forcing the alternatives to be: (0) A correct result (and no error object) (1) An error object (and no correct result) Ruling out: (0) Both a correct result and an error object (1) Neither a correct result nor an error object By “ruling out”, I mean “it's a compile error”, rather than “it's a pattern, and the community won't appreciate it if you deviate from it”. Panics as normal control flow are just as unidiomatic in Rust as they are in Go, but at least: (0) There's a decent (in fact, superior) alternative for error handling. (1) You don't risk leaking resources. RAII has that covered.
      - fauigerzigerk 10y ago
        I like the conceptual clarity of sum types, but in some cases they may not be flexible enough (same as exceptions). Consider the case of io.Reader: https://golang.org/pkg/io/#Reader https://golang.org/pkg/io/#Reader Read always returns the number of bytes read, and if an error occurs after some bytes have been read (or at EOF) it returns that error as well. It does feel a little dirty, but it's also efficient and pragmatic.
        catnaroek 10y ago
        > Read always returns the number of bytes read, and if an error occurs after some bytes have been read (or at EOF) it returns that error as well. Sum types can do this as well. In OCaml syntax: type result = | Success of int (* bytes read = buffer length *) | Error of int * err_info (* bytes read, error info *) class type reader = object (* attempt to fill the buffer *) method read : buffer -> result end > It does feel a little dirty, but it's also efficient and pragmatic. The pragmatic thing to do is to make illegal states irrepresentable, so that the programmer doesn't have to worry about them. There's literally no benefit to losing conceptual clarity.
        10y ago
- spriggan3 10y ago
  > I believe there are many languages that you could use that would have all of these features. That way you could use what you want and wouldn't have to complain about Go. We are talking about Go. Why do you basically say "f. you" to people when people points at some obvious flaws in the language ? people complain mostly because they are using it, if they were not, they wouldn't. Unfortunately your behavior is something I've seen often in the Go community.
  - jimjimjim 10y ago
    I apologize for the tone of my original comment. I've altered it to be hopefully less offensive. But.. I was responding a post that was pointing out many things that are known to not be present in the language. These features weren't forgotten or missed they were excluded when the language spec was being decided.
    - commentzorro 10y ago
      Even though all these features were purposely excluded by choice it's clear now in hindsight that some of these decisions are wrong. What I find so so weird is the tenacious responses when it's pointed out that Go has flaws. Why does Go get to be the one perfectly designed language? A decision can be made with tremendous thought but still be wrong.
      - mixedCase 10y ago
        >it's clear now in hindsight that some of these decisions are wrong For some usecases. For which you can just import Cheney's package, some other or roll your own. Which is Go's point: simple by default. For what I'm doing with Go I do not need nor want anything more than a string, I do not need a debugger so I don't use Delve, I don't need logging more complex than what the std libs interface offers... So why should I carry all that sort of baggage by default? If you need that stuff, feel free to import the adequate package or use a language that fits your purpose better. IMO Go is better treated as a DSL than a general purpose language, although I think the same of most languages.
catnaroek 10y ago
Although sum types make it easier to handle errors (or, more generally, multiple classes of results), Go probably won't adopt them anytime soon, if ever. Even then, not supporting more informative and structured error objects in the standard library is indeed very difficult to defend.

by TheDong 10y ago

jimjimjim 10y ago

I believe there are many languages that you could use that would have all of these features. That way you would have a language that would be more appropriate to your programming style without needing to add extra features to Go that possibly don't fit with Go's language style. (Note: post edited to remove snark.)

catnaroek 10y ago
I don't see how `panic` and `recover` are any simpler than exceptions. Could you explain? P.D.: The downvote didn't come from me.
- jimjimjim 10y ago
  Well, they are kind of more difficult than exceptions, but I think that's the point. Handling errors by use of an exception mechanism is discouraged in idiomatic go. A big part of the style and simplicity comes from not needing to worry about what possible exceptions could come bubbling up from a library stack and under what conditions. Even though people complain about the repetition of "if err !=nil" at least you know from the function declaration if an error is could occur.
  - catnaroek 10y ago
    FWIW, I don't have anything against checking errors - I agree that it's preferable to exceptions, but the way it happens to be done in Go is rather distasteful. A sum type, as suggested by TheDong, would make things clearer, by statically forcing the alternatives to be: (0) A correct result (and no error object) (1) An error object (and no correct result) Ruling out: (0) Both a correct result and an error object (1) Neither a correct result nor an error object By “ruling out”, I mean “it's a compile error”, rather than “it's a pattern, and the community won't appreciate it if you deviate from it”. Panics as normal control flow are just as unidiomatic in Rust as they are in Go, but at least: (0) There's a decent (in fact, superior) alternative for error handling. (1) You don't risk leaking resources. RAII has that covered.
    - fauigerzigerk 10y ago
      I like the conceptual clarity of sum types, but in some cases they may not be flexible enough (same as exceptions). Consider the case of io.Reader: https://golang.org/pkg/io/#Reader https://golang.org/pkg/io/#Reader Read always returns the number of bytes read, and if an error occurs after some bytes have been read (or at EOF) it returns that error as well. It does feel a little dirty, but it's also efficient and pragmatic.
      - catnaroek 10y ago
        > Read always returns the number of bytes read, and if an error occurs after some bytes have been read (or at EOF) it returns that error as well. Sum types can do this as well. In OCaml syntax: type result = | Success of int (* bytes read = buffer length *) | Error of int * err_info (* bytes read, error info *) class type reader = object (* attempt to fill the buffer *) method read : buffer -> result end > It does feel a little dirty, but it's also efficient and pragmatic. The pragmatic thing to do is to make illegal states irrepresentable, so that the programmer doesn't have to worry about them. There's literally no benefit to losing conceptual clarity.
        10y ago
spriggan3 10y ago
> I believe there are many languages that you could use that would have all of these features. That way you could use what you want and wouldn't have to complain about Go. We are talking about Go. Why do you basically say "f. you" to people when people points at some obvious flaws in the language ? people complain mostly because they are using it, if they were not, they wouldn't. Unfortunately your behavior is something I've seen often in the Go community.
- jimjimjim 10y ago
  I apologize for the tone of my original comment. I've altered it to be hopefully less offensive. But.. I was responding a post that was pointing out many things that are known to not be present in the language. These features weren't forgotten or missed they were excluded when the language spec was being decided.
  - commentzorro 10y ago
    Even though all these features were purposely excluded by choice it's clear now in hindsight that some of these decisions are wrong. What I find so so weird is the tenacious responses when it's pointed out that Go has flaws. Why does Go get to be the one perfectly designed language? A decision can be made with tremendous thought but still be wrong.
    - mixedCase 10y ago
      >it's clear now in hindsight that some of these decisions are wrong For some usecases. For which you can just import Cheney's package, some other or roll your own. Which is Go's point: simple by default. For what I'm doing with Go I do not need nor want anything more than a string, I do not need a debugger so I don't use Delve, I don't need logging more complex than what the std libs interface offers... So why should I carry all that sort of baggage by default? If you need that stuff, feel free to import the adequate package or use a language that fits your purpose better. IMO Go is better treated as a DSL than a general purpose language, although I think the same of most languages.

catnaroek 10y ago

Although sum types make it easier to handle errors (or, more generally, multiple classes of results), Go probably won't adopt them anytime soon, if ever. Even then, not supporting more informative and structured error objects in the standard library is indeed very difficult to defend.