Macro dockerfile_rs::COPY

macro_rules! COPY {
    (--from=$name:ident --chown=$user:ident:$group:ident $src:tt $dst:tt) => { ... };
    (--from=$name:ident --chown=$user:ident $src:tt $dst:tt) => { ... };
    (--chown=$user:ident:$group:ident $src:tt $dst:tt) => { ... };
    (--chown=$user:ident $src:tt $dst:tt) => { ... };
    ($src:tt $dst:tt) => { ... };
}

let copy = COPY!("." ".");
assert_eq!(copy.to_string(), r#"COPY "." ".""#);