What are some examples of closures in different programming languages?

Can you explain what closures are in programming?

Sure! A closure is a function that retains access to its lexical scope, even when the function is executed outside that scope.

Can you give me examples of closures in different programming languages?

Absolutely! In JavaScript, a closure can be created like this:

function outer() {
    let outerVar = 'I am outside!';
    function inner() {
        console.log(outerVar);
    }
    return inner;
}
const innerFunc = outer();
innerFunc(); // Outputs: I am outside!

In Python, you can create a closure like this:

def outer():
    outer_var = 'I am outside!'
    def inner():
        print(outer_var)
    return inner
inner_func = outer()
inner_func()  # Outputs: I am outside!

What about closures in languages like Ruby or Swift?

In Ruby, you can create a closure using a block:

def outer
    outer_var = 'I am outside!'
    inner = Proc.new { puts outer_var }
    inner.call
end
outer()  # Outputs: I am outside!

In Swift, closures are defined like this:

func outer() -> () -> Void {
    let outerVar = "I am outside!"
    return {
        print(outerVar)
    }
}
let innerFunc = outer()
innerFunc()  // Outputs: I am outside!