this post was submitted on 27 Sep 2023
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The ???? operator (programming.dev)
submitted 2 years ago* (last edited 2 years ago) by snaggen@programming.dev to c/rust@programming.dev
 

I found this funny.

The context is as explained by @laund@hachyderm.io

the issue is that you can't return from inside a closure, since the closure might be called later/elsewhere

and this post was the asnwer to the question by @antonok@fosstodon.org

you got me curious what the record for the longest ? operator chain on crates.io is

Original post: https://fosstodon.org/users/antonok/statuses/111134824451525448

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[–] BB_C@programming.dev 1 points 2 years ago* (last edited 2 years ago)

Is everyone genuinely liking this!

This is, IMHO, not a good style.

Isn't something like this much clearer?

// Add `as_cstr()` to `NixPath` trait first

let some_or_null_cstr = |v| v.map(NixPath::as_cstr)
  .unwrap_or(Ok(std::ptr::null()));

// `Option::or_null_cstr()` for `OptionᐸTᐳ`
// where `T:  NixPath` would make this even better
let source_cstr = some_or_null_cstr(&source)?;
let target_cstr = target.as_cstr()?;
let fs_type_cstr = some_or_null_cstr(&fs_type)?;
let data_cstr = some_or_null_cstr(&data)?;
let res = unsafe { .. };

Edit: using alternative chars to circumvent broken Lemmy sanitization.