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Announcing Rust 1.76.0 (blog.rust-lang.org)

submitted 9 months ago by snaggen to c/rust

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[–] [email protected] 17 points 9 months ago (1 children)

Oh, inspect has finally arrived! That will help a ton with debug logging.

[–] lambda 7 points 9 months ago* (last edited 9 months ago) (3 children)

Do you mind explaining? Maybe with the context of another languages equivalent?

[–] [email protected] 13 points 9 months ago (2 children)

let bar: Result<T, E> = ...;
let foo = bar.inspect(|value| log::debug("{}", value));

is equivalent to

let bar: Result<T, E> = ...;
let foo = bar.map(|value| {
    log::debug("{}", value);
    value
});

[–] xav 1 points 9 months ago

Warning: in the first case "value" is actually a shared reference, not a value.

[–] lambda 1 points 9 months ago

Elegant. Thanks!

[–] [email protected] 2 points 9 months ago

Looks vaguely like Stream::peek from Java, I think? There's an equivalent method in Iterator::inspect.

[–] owsei 1 points 9 months ago* (last edited 9 months ago)

it's just a way to use map with a reference instead of the value, by what I understood.

could be usefull for logging values in a Result so you can see it. However I think you can already do that by just mapping and returning the variable.