Macro array_function_dispatch

macro_rules! array_function_dispatch {
    (fn $name:ident($($arg:ident: $arg_ty:ty),*) -> Result<$ret:ty, $err:ty> $body:block, $func_name:expr) => { ... };
    (fn $name:ident($($arg:ident: $arg_ty:ty,)*) -> Result<$ret:ty, $err:ty> $body:block, $func_name:expr) => { ... };
    (fn $name:ident<$($type_param:ident $(: $type_bound:path)?),*>($($arg:ident: $arg_ty:ty),*) -> Result<$ret:ty, $err:ty> $body:block, $func_name:expr) => { ... };
    (fn $name:ident<$($type_param:ident $(: $type_bound:path)?),*>($($arg:ident: $arg_ty:ty,)*) -> Result<$ret:ty, $err:ty> $body:block, $func_name:expr) => { ... };
}