Add friend operator overloading

Doxyfile

@@ -4,7 +4,7 @@
 
 PROJECT_NAME           = "Firefly"
 PROJECT_BRIEF          = "Standalone library for vector calculations"
-PROJECT_NUMBER         = "3.0.0"
+PROJECT_NUMBER         = "3.1.0"
 
 
 FILE_PATTERNS          = *.cpp *.hpp

examples/main.cpp

@@ -14,6 +14,10 @@ int main() {
   std::cout << v3 << std::endl;
   std::cout << v4 << std::endl;
   std::cout << v5 << std::endl;
+  std::cout << 1 + v1 << std::endl;
+  std::cout << 1.2f + v1 << std::endl;
+  std::cout << std::complex<int>{1, 2} + v1 << std::endl;
+  std::cout << std::complex<float>{1.3, 2.5} + v1 << std::endl;
   std::cout << v1.norm() << std::endl;
   std::cout << v1.to_normalized().norm() << std::endl;
   std::cout << firefly::utilities::vector::angle_between(v1, v2) << std::endl

headers/firefly/vector.hpp

@@ -83,6 +83,7 @@ struct common_type<std::complex<T1>, std::complex<T2>> {
  */
 template <typename T1, typename T2>
 using common_type_t = typename common_type<T1, T2>::type;
+
 /**
  * @brief Concept that ensures the type is a complex number type.
  *
@@ -263,6 +264,23 @@ class vector : private std::array<T, Length> {
     return add(scalar);
   }
 
+  /**
+   * @brief Adds a scalar to a vector.
+   *
+   * This friend function allows adding a scalar to a vector, returning a new vector
+   * with the scalar added to each element of the original vector.
+   *
+   * @tparam U The type of the scalar.
+   * @param scalar The scalar value to add.
+   * @param vec The vector to add the scalar to.
+   *
+   * @return A new vector with the result of the addition.
+   */
+  template <vector_type U>
+  friend constexpr auto operator+(U const scalar, vector<T, Length> const &vec) {
+    return vec + scalar;
+  }
+
   /**
    * @brief Performs element-wise addition of two vectors using the `+=` operator.
    *
@@ -357,6 +375,23 @@ class vector : private std::array<T, Length> {
     return subtract(scalar);
   }
 
+  /**
+   * @brief Subtracts a scalar to a vector.
+   *
+   * This friend function allows subtracting a scalar to a vector, returning a new vector
+   * with the scalar subtracted from each element of the original vector.
+   *
+   * @tparam U The type of the scalar.
+   * @param scalar The scalar value to subtract.
+   * @param vec The vector to add the scalar to.
+   *
+   * @return A new vector with the result of the subtraction.
+   */
+  template <vector_type U>
+  friend constexpr auto operator-(U const scalar, vector<T, Length> const &vec) {
+    return vec - scalar;
+  }
+
   /**
    * @brief Performs element-wise subtraction of another vector using the `-=` operator.
    *
@@ -485,6 +520,23 @@ class vector : private std::array<T, Length> {
     return scale(scalar);
   }
 
+  /**
+   * @brief Scales a vector by a scalar.
+   *
+   * This friend function allows scaling a vector by a scalar, returning a new vector
+   * with each element of the original vector multiplied by the scalar.
+   *
+   * @tparam U The type of the scalar.
+   * @param scalar The scalar value to scale by.
+   * @param vec The vector to scale.
+   *
+   * @return A new vector with the result of the scaling.
+   */
+  template <vector_type U>
+  friend constexpr auto operator*(U const scalar, vector<T, Length> const &vec) {
+    return vec * scalar;
+  }
+
   /**
    * @brief Scales the vector in place using the `*=` operator.
    *
@@ -515,6 +567,23 @@ class vector : private std::array<T, Length> {
     return scale(1 / scalar);
   }
 
+  /**
+   * @brief Performs inverse scaling of a vector by a scalar.
+   *
+   * This friend function allows inverse scaling of a vector by a scalar, returning a new vector
+   * with each element of the original vector divided by the scalar.
+   *
+   * @tparam U The type of the scalar.
+   * @param scalar The scalar value to inversely scale by.
+   * @param vec The vector to scale.
+   *
+   * @return A new vector with the result of the inverse scaling.
+   */
+  template <vector_type U>
+  friend constexpr auto operator/(U const scalar, vector<T, Length> const &vec) {
+    return vec / scalar;
+  }
+
   /**
    * @brief Scales the vector in place using the `/=` operator.
    *