smiletolerantly comments on things rust shipped without (2015)

[–] smiletolerantly@awful.systems 1 point 1 year ago (4 children)

Drop if-let

Over my cold dead body. if-let-else is such a fantastic pattern. Makes everything an order of magnitude more readable. Works so nicely for unwrapping opts/errs.

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[–] TehPers@beehaw.org 1 point 1 year ago (3 children)

Their suggested replacement is closer to C#'s is keyword:

if foo is Some(foo) {
    // ...
}

The issue here is that we still have let-else, which can't be translated as easily:

let Some(foo) = foo else {
    todo!();
};

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[–] soc@programming.dev 1 point 1 year ago* (last edited 1 year ago) (2 children)

I don't think the alternative to let-else is too bad.

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[–] TehPers@beehaw.org 1 point 1 year ago (1 child)

That's not an alternative, it's removing let-else entirely. It's equivalent to this:

let i = if let Some(i) = opt_number {
    i
} else {
    return 0;
};

let-else is specifically a feature that allows you to use a refutable pattern to deconstruct a value by providing a diverging else branch.

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[–] soc@programming.dev 1 point 1 year ago* (last edited 1 year ago)

Removing let-else is the whole point of the linked article series:

Being able to do to everything Rust does, but without Rust's zoo of if-then-else, match, if-let, let-else etc.

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