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Comment by aravindet | Hacker News Reader

The todo keyword https://gleam.run/book/tour/todo.html is brilliant. Are there any other languages that have this?

Rust has the `todo!()` macro: https://doc.rust-lang.org/std/macro.todo.html

Haskell has "typed holes": https://downloads.haskell.org/~ghc/7.10.1/docs/html/users_gu...

Elm has `Debug.todo`. If you were to use this, it allows your app to compile in development but the app would crash should it hit this code.

Elm's compiler will prevent you from creating a production application with a `Debug.todo` still in place.

Probably based a little on this: https://doc.rust-lang.org/std/macro.todo.html

You can get a similar effect in Elixir with # TODO comments if you're using Credo.

It's just a code comment, but by default Credo will exit non-zero if it sees one so if Credo is part of your CI pipeline it will fail it by default.

I'm one of those annoying people who puts # TODO comments all over my code though, so I set Credo so that TODO's wouldn't fail the build.

AFAIK there's no reason support, but you can make a whole in Scala using ??? as the right-hand side.

it's not the same, but it's almost idiomatic to leave unfinished python code with "..." (the ellipsis object)

    def foo(bar, baz):
        ...

is a valid (empty) python function

Oh, interesting. I’ve always used “pass” for this.

Yeah, but this is best used for abstract methods or type stubs. I think in 'real code' you would want to raise NotImplementedError, or even (if you use mypy) potentially return a NoReturn

ie: from typing import Any, NoReturn

    def foo(bar: Any, baz: Any) -> NoReturn:
        raise NotImplementedError

Perl has ellipsis which will die on use.

kotlin has TODO("reason")

Scala has `???`, which does a similar thing.

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