Math: avoid copypaste code in DualComplex.

Ugh this class is ugly (but works!).

src/Magnum/Math/Dual.h

@@ -201,7 +201,9 @@ template<class T> class Dual {
     }                                                                       \
     Type<T> operator-(const Math::Dual<Underlying<T>>& other) const {       \
         return Math::Dual<Underlying<T>>::operator-(other);                 \
-    }                                                                       \
+    }
+/* DualComplex needs its own special implementation of multiplication/division */
+#define MAGNUM_DUAL_SUBCLASS_MULTIPLICATION_IMPLEMENTATION(Type, Underlying) \
     template<class U> Type<T> operator*(const Math::Dual<U>& other) const { \
         return Math::Dual<Underlying<T>>::operator*(other);                 \
     }                                                                       \

src/Magnum/Math/DualComplex.h

@@ -339,27 +339,9 @@ template<class T> class DualComplex: public Dual<Complex<T>> {
             return Vector2<T>(((*this)*DualComplex<T>(vector)).dual());
         }
 
-        /* Verbatim copy of DUAL_SUBCLASS_IMPLEMENTATION(), as we need to hide
-           Dual's operator*() and operator/() */
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        DualComplex<T> operator-() const {
-            return Dual<Complex<T>>::operator-();
-        }
-        DualComplex<T>& operator+=(const Dual<Complex<T>>& other) {
-            Dual<Complex<T>>::operator+=(other);
-            return *this;
-        }
-        DualComplex<T> operator+(const Dual<Complex<T>>& other) const {
-            return Dual<Complex<T>>::operator+(other);
-        }
-        DualComplex<T>& operator-=(const Dual<Complex<T>>& other) {
-            Dual<Complex<T>>::operator-=(other);
-            return *this;
-        }
-        DualComplex<T> operator-(const Dual<Complex<T>>& other) const {
-            return Dual<Complex<T>>::operator-(other);
-        }
-        #endif
+        MAGNUM_DUAL_SUBCLASS_IMPLEMENTATION(DualComplex, Vector2)
+        /* Not using MAGNUM_DUAL_SUBCLASS_MULTIPLICATION_IMPLEMENTATION(), as
+           we have special multiplication/division implementation */
 
     private:
         /* Just to be sure nobody uses this, as it wouldn't probably work with

src/Magnum/Math/DualQuaternion.h

@@ -355,6 +355,7 @@ template<class T> class DualQuaternion: public Dual<Quaternion<T>> {
         }
 
         MAGNUM_DUAL_SUBCLASS_IMPLEMENTATION(DualQuaternion, Quaternion)
+        MAGNUM_DUAL_SUBCLASS_MULTIPLICATION_IMPLEMENTATION(DualQuaternion, Quaternion)
 };
 
 /** @debugoperator{Magnum::Math::DualQuaternion} */

src/Magnum/Math/Test/DualTest.cpp

@@ -171,6 +171,7 @@ template<class T> class BasicDualVec2: public Math::Dual<Math::Vector2<T>> {
         template<class ...U> constexpr BasicDualVec2(U&&... args): Math::Dual<Math::Vector2<T>>(args...) {}
 
         MAGNUM_DUAL_SUBCLASS_IMPLEMENTATION(BasicDualVec2, Math::Vector2)
+        MAGNUM_DUAL_SUBCLASS_MULTIPLICATION_IMPLEMENTATION(BasicDualVec2, Math::Vector2)
 };
 
 typedef BasicDualVec2<Float> DualVec2;