Functional Language Features in Rust – Iterators and Closures

Re:Functional Language Features in Rust – Iterators and Clos... by bigger_cheese on Tuesday March 07, 2017 @06:00PM (#13815991)

That was really well written. As I was reading through the example code in the section about closures

    let add_one = |x| x + 1;
    let five = add_one(4);

I thought to myself "hmm I wonder what happens if I were to call the code with a float rather than an int?"

Answered my question a few paragraphs down. Kudos.

Is it possible to write a generic closure? i.e something that would add 1 to any numeric type.

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Re:Functional Language Features in Rust – Iterators and Clos... by Manishearth on Tuesday March 07, 2017 @06:14PM (#13816127)

> Answered my question a few paragraphs down. Kudos.

I absolutely love it when a blog post, talk, or docs like these do that.

Especially during talks. Often the speaker will say something and it will immediately pop up questions in my mind which I really really want to ask but of course I should wait till the end. And then they answer it in the next slide. Perfect :)

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Re:Functional Language Features in Rust – Iterators and Clos... by steveklabnik on Tuesday March 07, 2017 @06:06PM (#13816056)

Thanks!

To answer your last question, not yet. There was an RFC for this, but it was recently postponed; closures rely heavily on traits and we are in the process of re-doing the internals of the trait system. If I remember the reason correctly.

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Re:Functional Language Features in Rust – Iterators and Clos... by eddyb on Tuesday March 07, 2017 @06:33PM (#13816318)

Indeed, the way you would be generic over generic closures would be "type HRTB" (e.g. F: for<T: Clone> Fn(&T) -> T), which depends on the trait system overhaul, just like ATC.

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Re:Functional Language Features in Rust – Iterators and Clos... by TheCycoONE on Tuesday March 07, 2017 @09:07PM (#13817208)

The whole new Rust Book is quite well written. It was my first resource when I read it a few months ago and I found it easy to understand everything it covered - even lifetimes which I completely failed to get from the original book or other online resources. I look forward to the rest of the chapters being filled in.

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