What is the most idiomatic way to concatenate integer variables?

Question

The compiler doesn't seem to infer that the integer variables are passed as string literals into the concat! macro, so I found the stringify! macro that converts these integer variables into string literals, but this looks ugly:

fn date(year: u8, month: u8, day: u8) -> String
{
    concat!(stringify!(month), "/",
            stringify!(day), "/",
            stringify!(year)).to_string()
}

Answer 1

concat! takes literals and produces a &'static str at compile time. You should use format! for this:

fn date(year: u8, month: u8, day: u8) -> String {
    format!("{}/{}/{}", month, day, year)
}