How do I transform &str to ~str in Rust?

Question

This is for the current 0.6 Rust trunk by the way, not sure the exact commit.

Let's say I want to for each over some strings, and my closure takes a borrowed string pointer argument (&str). I want my closure to add its argument to an owned vector of owned strings ~[~str] to be returned. My understanding of Rust is weak, but I think that strings are a special case where you can't dereference them with * right? How do I get my strings from &str into the vector's push method which takes a ~str?

Here's some code that doesn't compile

fn read_all_lines() -> ~[~str] {
    let mut result = ~[];
    let reader = io::stdin();
    let util = @reader as @io::ReaderUtil;
    for util.each_line |line| {
        result.push(line);
    }
    result
}

It doesn't compile because it's inferring result's type to be [&str] since that's what I'm pushing onto it. Not to mention its lifetime will be wrong since I'm adding a shorter-lived variable to it.

I realize I could use ReaderUtil's read_line() method which returns a ~str. But this is just an example.

So, how do I get an owned string from a borrowed string? Or am I totally misunderstanding.