Macro itoa

macro_rules! itoa {
    ($into_dtoa:expr) => { ... };
}

Quickly format an integer to a &str

This creates an ItoaTmp from an Integer, returns the output &str, and immediately goes out of scope.

The function signature would look something like:

fn itoa<I: Integer>(integer: I) -> &'tmp str
where
    'tmp: FreedAtEndOfStatement

ItoaTmp is created and immediately dropped, thus it cannot be stored:

let x = itoa!(10);
        ^^^^^^^^^- temporary value is freed at the end of this statement

assert_eq!(x, "10");
------------------- compile error: borrow later used here

You must use the &str in 1 single statement:

assert_eq!(itoa!(10), "10"); // ok

if itoa!(10) == "10" {
    // ok
}

// ok
let string: String = itoa!(10).to_string();
assert_eq!(string, "10");

The macro expands to ItoaTmp::new().format(x):

// These are the same.

itoa!(10);

readable::toa::ItoaTmp::new().format(10);