From e6595cf9c527e97198806c48aa0a14ae8e895e87 Mon Sep 17 00:00:00 2001
From: Nao Pross <naopross@thearcway.org>
Date: Mon, 21 Jan 2019 00:39:13 +0100
Subject: Add member operator =, +=, -=, *= overloads for basic_vec

---
 example.cpp |  6 ++++++
 mmvec.hpp   | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/example.cpp b/example.cpp
index e72d65b..3a00f58 100644
--- a/example.cpp
+++ b/example.cpp
@@ -21,6 +21,8 @@ int main(int argc, char *argv[]) {
 	std::cout << "u * v = " << u * v << std::endl;
 	std::cout << std::endl;
 
+	u += v;
+
 	// three dimensional vectors
 	std::cout << "three dimensional (double) vectors" << std::endl;
 
@@ -37,6 +39,8 @@ int main(int argc, char *argv[]) {
 	std::cout << "spherical(a) = " << a.spherical() << std::endl;
 	std::cout << std::endl;
 
+	a -= b;
+
 	// two dimensional vector
 	std::cout << "two dimensional (complex) vectors" << std::endl;
 
@@ -52,5 +56,7 @@ int main(int argc, char *argv[]) {
 	std::cout << "polar(j) = " << j.polar() << std::endl;
 	std::cout << std::endl;
 
+	j *= 10;
+
 	return 0;
 }
diff --git a/mmvec.hpp b/mmvec.hpp
index 5173e85..0f21d22 100644
--- a/mmvec.hpp
+++ b/mmvec.hpp
@@ -53,9 +53,23 @@ struct mm::basic_vec : public std::array<T, d> {
     template<std::size_t n> basic_vec(const basic_vec<T, n>& other);
 
     T length() const;
+
+    template<std::size_t n>
+    basic_vec<T, d>& operator=(const mm::basic_vec<T, n>& other);
+
+    template<std::size_t n>
+    basic_vec<T, d>& operator+=(const mm::basic_vec<T, n>& other);
+
+    template<std::size_t n>
+    basic_vec<T, d>& operator-=(const mm::basic_vec<T, n>& other);
+
+
+    basic_vec<T, d>& operator*=(const T& scalar);
 };
 
 
+// member functions for basic_vec
+
 template<typename T, std::size_t d>
 mm::basic_vec<T, d>::basic_vec() : std::array<T, d>() {
     this->fill(basic_vec<T, d>::null_element);
@@ -76,13 +90,8 @@ template<std::size_t n>
 mm::basic_vec<T, d>::basic_vec(const mm::basic_vec<T, n>& other) {
     // construct with empty values
     basic_vec();
-
-    static_assert(
-        d >= n, 
-        "cannot copy higher dimensional vector into a smaller one"
-    );
-
-    std::copy(other.begin(), other.end(), this->begin());
+    // uses operator=
+    *this = other;
 }
 
 template<typename T, std::size_t d>
@@ -95,6 +104,45 @@ T mm::basic_vec<T, d>::length() const {
     ));
 }
 
+
+// memeber operator overloads for basic_vec
+
+template<typename T, std::size_t d>
+template<std::size_t n>
+mm::basic_vec<T, d>& mm::basic_vec<T, d>::operator=(const mm::basic_vec<T, n>& other) {
+    static_assert(
+        d >= n, 
+        "cannot copy higher dimensional vector into a smaller one"
+    );
+
+    std::copy(other.begin(), other.end(), this->begin());
+
+    return *this;
+}
+
+template<typename T, std::size_t d>
+template<std::size_t n>
+mm::basic_vec<T, d>& mm::basic_vec<T, d>::operator+=(const mm::basic_vec<T, n>& other) {
+    *this = *this + other;
+    return *this;
+}
+
+template<typename T, std::size_t d>
+template<std::size_t n>
+mm::basic_vec<T, d>& mm::basic_vec<T, d>::operator-=(const mm::basic_vec<T, n>& other) {
+    *this = *this - other;
+    return *this;
+}
+
+template<typename T, std::size_t d>
+mm::basic_vec<T, d>& mm::basic_vec<T, d>::operator*=(const T& scalar) {
+    *this = *this * scalar;
+    return *this;
+}
+
+
+// operator overloads for basic_vec
+
 template<typename T, std::size_t d>
 mm::basic_vec<T, d> operator+(const mm::basic_vec<T, d>& rhs, const mm::basic_vec<T, d>& lhs) {
     mm::basic_vec<T, d> out;
@@ -146,7 +194,9 @@ std::ostream& operator<<(std::ostream& os, const mm::basic_vec<T, d>& v) {
     return os;
 }
 
-// actual classes to use in your code
+
+// actual vectors to use in your code
+
 template<typename T, std::size_t d>
 class mm::vec: public mm::basic_vec<T, d> {
 public:
@@ -156,7 +206,10 @@ public:
     vec(const basic_vec<T, n>& other) : basic_vec<T, d>(other) {}
 };
 
+
 // three dimensional specialization with a static cross product
+// TODO: specialize operator+ for spherical coordinates
+
 template<typename T>
 class mm::vec3 : public mm::basic_vec<T, 3> {
 public:
@@ -211,7 +264,10 @@ mm::vec3<T> mm::vec3<T>::cross(const vec3<T>& rhs, const vec3<T>& lhs) {
     return res;
 }
 
+
 // two dimensional specialization with a polar conversion
+// TODO: specialize operator+ for polar coordinates
+
 template<typename T>
 class mm::vec2: public mm::basic_vec<T, 2> {
 public:
-- 
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