macro_rules! string_from {
    () => { ... };
    ("") => { ... };
    (->$from:expr) => { ... };
    (&$from:expr) => { ... };
    (String::from($from:expr)) => { ... };
    ($from:expr) => { ... };
    (&$($from_tt:tt)+) => { ... };
    ($($from_tt:tt)+) => { ... };
}
Expand description

string_from macro. based on Strong::from, but no arg can generate String::new()