macro_rules! xlink_error {
($code:expr, $category:ident, $message:expr, $details:expr) => { ... };
($code:expr, $category:ident, $message:expr, $details:expr, $($method:ident($value:expr)),+) => { ... };
}macro_rules! xlink_error {
($code:expr, $category:ident, $message:expr, $details:expr) => { ... };
($code:expr, $category:ident, $message:expr, $details:expr, $($method:ident($value:expr)),+) => { ... };
}