[PATCH v1 27/28] rust: types: add `Either` type

Miguel Ojeda
2022-11-10T16:45:39Z

From: Wedson Almeida Filho <wedsonaf@gmail.com>

Introduce the new `types` module of the `kernel` crate with
`Either` as its first type.

`Either<L, R>` is a sum type that always holds either a value
of type `L` (`Left` variant) or `R` (`Right` variant).

For instance:

struct Executor {
queue: Either<BoxedQueue, &'static Queue>,
}

Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
rust/kernel/lib.rs | 1 +
rust/kernel/types.rs | 12 ++++++++++++
2 files changed, 13 insertions(+)
create mode 100644 rust/kernel/types.rs

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index a3abc110ff97..53040fa9e897 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -31,6 +31,7 @@ mod static_assert;
#[doc(hidden)]
pub mod std_vendor;
pub mod str;
+pub mod types;

#[doc(hidden)]
pub use bindings;
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
new file mode 100644
index 000000000000..3b0c44769708
--- /dev/null
+++ b/rust/kernel/types.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel types.
+
+/// A sum type that always holds either a value of type `L` or `R`.
+pub enum Either<L, R> {
+ /// Constructs an instance of [`Either`] containing a value of type `L`.
+ Left(L),
+
+ /// Constructs an instance of [`Either`] containing a value of type `R`.
+ Right(R),
+}
--
2.38.1