I am well aware, I wrote quite a lot of Rust, including professionally. I’m not necessarily talking about the “clear happy path”, even though that is relatively nice to have (Rust sort-of allows that with the ? sugar and the pseudo-functor and pseudo-monad methods on wrappers); I’m talking more about the fine line between the overly verbose lists of all the errors that a function could produce (thiserror-style) or just a single messy error type that makes error handling difficult (anyhow-style). There surely must be something in between there that is concise, type-safe, and composable, but I haven’t seen it in any language yet.
In my case, I don’t usually encounter cases where I can’t just ?. But when I do, just make an error enum (kinda like thiserror) that encapsulates the possible errors + possibly adds more.
On the call site, just convert to string if I don’t care about specifics (anyhow-style).
I don’t find this much painful.
Concise: not much on the declaration side, since you have to create an entire enum for each function in worst-case scenario. But on code side, it’s just .map_err(MyError)?.
Type-safe: can’t beat errors as enum values wrapped in Result.
Composable: i don’t think you can beat rust enums in composability.
I don’t use anyhow/thiserror, so I’m not sure. But I believe thiserror fixes the conciseness issue for this.
I am well aware, I wrote quite a lot of Rust, including professionally. I’m not necessarily talking about the “clear happy path”, even though that is relatively nice to have (Rust sort-of allows that with the
?sugar and the pseudo-functor and pseudo-monad methods on wrappers); I’m talking more about the fine line between the overly verbose lists of all the errors that a function could produce (thiserror-style) or just a single messy error type that makes error handling difficult (anyhow-style). There surely must be something in between there that is concise, type-safe, and composable, but I haven’t seen it in any language yet.In my case, I don’t usually encounter cases where I can’t just
?. But when I do, just make an error enum (kinda like thiserror) that encapsulates the possible errors + possibly adds more.On the call site, just convert to string if I don’t care about specifics (anyhow-style).
I don’t find this much painful.
Concise: not much on the declaration side, since you have to create an entire enum for each function in worst-case scenario. But on code side, it’s just
.map_err(MyError)?.Type-safe: can’t beat errors as enum values wrapped in Result.
Composable: i don’t think you can beat rust enums in composability.
I don’t use anyhow/thiserror, so I’m not sure. But I believe thiserror fixes the conciseness issue for this.