diff -r edb95d2b83cc -r d2acaaddd9af src/types.rs
--- a/src/types.rs	Sun Nov 10 09:02:57 2024 -0500
+++ b/src/types.rs	Tue Dec 31 09:12:43 2024 -0500
@@ -57,7 +57,8 @@
                  + CastFrom<u128> + CastFrom<usize>
                  + CastFrom<i8>   + CastFrom<i16> + CastFrom<i32> + CastFrom<i64>
                  + CastFrom<i128> + CastFrom<isize>
-                 + CastFrom<f32>  + CastFrom<f64> {
+                 + CastFrom<f32>  + CastFrom<f64>
+                 + HasScalarField<Field = Self> {
 
     const ZERO : Self;
     const ONE : Self;
@@ -106,6 +107,9 @@
             const RANGE_MAX : Self = <$type>::MAX;
             const RANGE_MIN : Self = <$type>::MIN;
         }
+        impl HasScalarField for $type {
+            type Field = $type;
+        }
     )* }
 }
 
@@ -163,3 +167,54 @@
 }
 */
 
+
+/// Trait for on-demand cloning as of `Self` as `Target`.
+///
+/// Blanket implementations clone references, but do nothing if `Self` equals `Target`.
+///
+/// The idea is to allow other traits to be implemented generically, similar to now one
+/// can work with references and owned values through [`std::borrow::Borrow`], but, in
+/// contrast to the latter, this trait will provide an owned value instead of reference.
+pub trait CloneIfNeeded<Target> {
+    /// Clone `self` if needed as `Target`.
+    fn clone_if_needed(self) -> Target;
+}
+
+impl<'a, T : Clone> CloneIfNeeded<T> for &'a T {
+    #[inline]
+    /// Clone
+    fn clone_if_needed(self) -> T {
+        self.clone()
+    }
+}
+
+impl<'a, T : Clone> CloneIfNeeded<T> for &'a mut T {
+    #[inline]
+    /// Clone
+    fn clone_if_needed(self) -> T {
+        self.clone()
+    }
+}
+
+impl<'a, T> CloneIfNeeded<T> for T {
+    #[inline]
+    /// No clone needed
+    fn clone_if_needed(self) -> T {
+        self
+    }
+}
+
+/// Trait for objects that have an associated scalar field.
+pub trait HasScalarField {
+    type Field : Num;
+}
+
+/// Trait for objects that have an associated real field.
+pub trait HasRealField : HasScalarField<Field = Self::RealField> {
+    type RealField : Float;
+}
+
+impl<T> HasRealField for T where T : HasScalarField, T::Field : Float {
+    type RealField = T::Field;
+}
+