coremem_types: Enum: add constructors

crates/types/src/compound/enumerated.rs

@@ -128,6 +128,26 @@ where
 #[derive(Copy, Clone, Default, PartialEq)]
 struct Enum<D, L>(D, L);
 
+impl<P: Peano, L> Enum<(Discr<P>,), L> {
+    pub fn new<Variants>(v: Variants) -> Self
+    where
+        Variants: IntoList<List=L>,
+        L: list::Meta<Length=P>,
+    {
+        Enum((Discr::default(),), v.into_list())
+    }
+}
+impl<L> Enum<(), L> {
+    pub fn internally_discriminated<Variants>(v: Variants) -> Self
+    where
+        Variants: IntoList<List=L>,
+        L: list::Meta + Indexable<P0>,
+        list::ElementAt<P0, L>: DiscriminantCodable<<L as list::Meta>::Length>,
+    {
+        Enum((), v.into_list())
+    }
+}
+
 trait EnumRequirements {
     type NumVariants: Peano;
     fn decode_discr(&self) -> Discr<Self::NumVariants>;
@@ -300,4 +320,13 @@ mod test {
         e.set::<P0>(BoxedF32(0f32));
         assert_eq!(e.dispatch(ReadReceiver), 0);
     }
+
+    #[test]
+    fn new() {
+        let e = Enum::new((5u32, 4i32));
+        assert_eq!(e.dispatch(ReadReceiver), 5);
+
+        let e = Enum::internally_discriminated((BoxedF32(4f32), -1i32));
+        assert_eq!(e.dispatch(ReadReceiver), 4);
+    }
 }