graydon2 | things rust shipped without
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  • smiletolerantly@awful.systems
    0·
    1 year ago

    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.

    • TehPers@beehaw.orgEnglish
      0·
      1 year ago

      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!();
};
        • TehPers@beehaw.orgEnglish
          0·
          1 year ago

          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.