Macro format_args_cx

macro_rules! format_args_cx {
    ($cx:expr, $fmt:literal, $($args:tt)*) => { ... };
    ($cx:expr, $fmt:literal) => { ... };
    (@go ($cx:ident, $fmt:literal; ^$head:expr, $($tail:tt)*) -> ($($accum:tt)*)) => { ... };
    (@go ($cx:ident, $fmt:literal; $head:expr, $($tail:tt)*) -> ($($accum:tt)*)) => { ... };
    (@go ($cx:ident, $fmt:literal; ^$head:expr) -> ($($accum:tt)*)) => { ... };
    (@go ($cx:ident, $fmt:literal; $head:expr) -> ($($accum:tt)*)) => { ... };
    (@as_expr $e:expr) => { ... };
}