[steveklabnik]

As a Rubyist, I found the closure syntax quite comfortable, as they're almost identical. Passing a closure or lambda to some function foo:

        x = foo {|x|   x + 1 }    # Ruby
    let x =  foo(|x| { x + 1 }); //Rust
    let x =  foo(|x|   x + 1 );  // single expressions don't need {}s

That said, I'm not sure what the exact reason was for choosing the syntax, as that was before my time.

[aturon]

> That said, I'm not sure what the exact reason was for choosing the syntax, as that was before my time.

I think the reason is just that it's very concise, and lightweight closure syntax makes things like `Option::map` feel like first-class parts of the language. The closure you pass just sort of seamlessly "blends in".

Note that having especially sugary here is not so uncommon, for example Haskell has `\x -> blah` for Rust's `|x| blah`.

I'm personally very happy that the closure syntax is as concise as it is.