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Seems cool, but is a whole crate worth it for the `.context` function when you could just use e.g., `.map_err(|source| Error::Opening { source, filename })`? Se

Seems cool, but is a whole crate worth it for the `.context` function when you could just use e.g., `.map_err(|source| Error::Opening { source, filename })`? Seems like all `.context` provides is not not needing to name the originating error? (And obviously the `#[snafu(display(...))]` macros could just be moved into a `impl Debug for Error`.)

shepmaster 5y ago
> but is a whole crate worth it Yes. I'm not sure exactly what other response you'd expect from the author/maintainer of a library when they've already made a post encouraging other people to use it. ¯\_(ツ)_/¯ > when you could just use e.g., `.map_err(|source| Error::Opening { source, filename })` That's not equivalent, as `filename` is a `&str` but becomes a `String` when stored in the error. SNAFU automatically calls `Into::into` for you, so the closest would be: .map_err(|source| Error::Opening { source, filename: filename.into() }) > Seems like all `.context` provides There's also the possibility of automatic construction of values (backtraces, location information, the current time, things captured from globals / thread locals, etc.) Beyond `.context`, SNAFU also implements the `Error` trait (and associated methods like `Error::source`). There's also convenience methods and macros to create leaf errors, those that originate in your code. > obviously the `#[snafu(display(...))]` macros could just be moved into a `impl Debug for Error` I'll assume you mean `Display`, not `Debug`. That also not quite true, as SNAFU offers a shorthand syntax that isn't yet in stable Rust: "Unable to read {filename}" would need to be one of "Unable to read {}", filename "Unable to read {filename}", filename = filename > like all [...] provides [...] obviously [..] could just be moved All code could have been written by your own hand or otherwise inlined. Your response feels (needlessly) highly dismissive of another person's work.
- bobbylarrybobby 5y ago
  Thanks for your reply. I guess my question should really have been a statement: “based on this example, I don’t think it’s worth it”. But the info you provided does make it seem worthwhile. Cheers

shepmaster 5y ago

> but is a whole crate worth it Yes. I'm not sure exactly what other response you'd expect from the author/maintainer of a library when they've already made a post encouraging other people to use it. ¯\_(ツ)_/¯ > when you could just use e.g., `.map_err(|source| Error::Opening { source, filename })` That's not equivalent, as `filename` is a `&str` but becomes a `String` when stored in the error. SNAFU automatically calls `Into::into` for you, so the closest would be: .map_err(|source| Error::Opening { source, filename: filename.into() }) > Seems like all `.context` provides There's also the possibility of automatic construction of values (backtraces, location information, the current time, things captured from globals / thread locals, etc.) Beyond `.context`, SNAFU also implements the `Error` trait (and associated methods like `Error::source`). There's also convenience methods and macros to create leaf errors, those that originate in your code. > obviously the `#[snafu(display(...))]` macros could just be moved into a `impl Debug for Error` I'll assume you mean `Display`, not `Debug`. That also not quite true, as SNAFU offers a shorthand syntax that isn't yet in stable Rust: "Unable to read {filename}" would need to be one of "Unable to read {}", filename "Unable to read {filename}", filename = filename > like all [...] provides [...] obviously [..] could just be moved All code could have been written by your own hand or otherwise inlined. Your response feels (needlessly) highly dismissive of another person's work.

bobbylarrybobby 5y ago
Thanks for your reply. I guess my question should really have been a statement: “based on this example, I don’t think it’s worth it”. But the info you provided does make it seem worthwhile. Cheers