Macro impl_fmt_display

macro_rules! impl_fmt_display {
    () => { ... };
    ($field:ident, $v:ident, $self:ident) => { ... };
    ($field:ident => [$($arr:tt)+], $v:ident, $self:ident) => { ... };
    ([$($arr:tt)+], $v:ident) => { ... };
}