Macro punc 

macro_rules! punc {
    (value $value:expr) => { ... };
    (pairs $first:expr; $($punctuation:expr => $next:expr),+ $(,)?) => { ... };
    ($value:ty) => { ... };
}

Names or constructs a nonempty comma-punctuated sequence.

• punc!(T) names Punctuated<T>.
• punc!(value first) constructs one value.
• punc!(pairs first; comma => second, ...) constructs a sequence while retaining every supplied typed comma and its span.