/// Cache a value in a [thread_local!]. Supports synchronous and asynchronous
/// initializers
///
/// ```
/// #[macro_use]
/// use orchid_base::tl_cache;
///
/// // simple synchronous case
/// let foo = tl_cache!(Rc<Vec<usize>>: vec![0; 1024]);
/// async {
///   async fn complex_operation(x: usize) -> usize { x + 1 }
///   // async case
///   let bar = tl_cache!(async usize: complex_operation(0).await)
/// }
/// ```
#[macro_export]
macro_rules! tl_cache {
	($ty:ty : $expr:expr) => {{
		thread_local! {
			static V: $ty = $expr;
		}
		V.with(|v| v.clone())
	}};
	(async $ty:ty : $expr:expr) => {{
		type CellType = std::cell::OnceCell<$ty>;
		thread_local! {
			static V: CellType = std::cell::OnceCell::default();
		}
		match V.with(|cell: &CellType| cell.get().cloned()) {
			Some(val) => val as $ty,
			None => {
				let val = $expr;
				let _ = V.with(|cell: &CellType| cell.set(val.clone()));
				val as $ty
			},
		}
	}};
}