Added template memento pattern

docs/test_cases.md

@@ -24,6 +24,7 @@
  * [t00023](./test_cases/t00023.md) - Strategy pattern
  * [t00024](./test_cases/t00024.md) - Proxy pattern
  * [t00025](./test_cases/t00025.md) - Template proxy pattern
+ * [t00026](./test_cases/t00026.md) - Template memento pattern
 ## Sequence diagrams
  * [t20001](./test_cases/t20001.md) - Basic sequence diagram
 ## Configuration diagrams

docs/test_cases/t00026.md

@@ -0,0 +1,83 @@
+# t00026 - Template memento pattern
+## Config
+```yaml
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00026_class:
+    type: class
+    glob:
+      - ../../tests/t00026/t00026.cc
+    using_namespace:
+      - clanguml::t00026
+    include:
+      namespaces:
+        - clanguml::t00026
+
+```
+## Source code
+File t00026.cc
+```cpp
+#include <iostream>
+#include <memory>
+#include <unordered_map>
+
+namespace clanguml {
+namespace t00026 {
+
+template <typename T> class Memento {
+public:
+    Memento(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    T value() const { return m_value; }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Originator {
+public:
+    Originator(T &&v)
+        : m_value(std::forward<T>(v))
+    {
+    }
+
+    Memento<T> memoize_value() const { return Memento<T>{m_value}; }
+
+    void load(const Memento<T> &m) { m_value = m.value(); }
+
+    void print() const { std::cout << m_value << std::endl; }
+
+    void set(T &&v) { m_value = std::forward<T>(v); }
+
+private:
+    T m_value;
+};
+
+template <typename T> class Caretaker {
+public:
+    Memento<T> &state(const std::string &n) { return m_mementos.at(n); }
+
+    void set_state(const std::string &s, Memento<T> &&m)
+    {
+        m_mementos.try_emplace(s, std::move(m));
+    }
+
+private:
+    std::unordered_map<std::string, Memento<T>> m_mementos;
+};
+
+struct StringMemento {
+    Caretaker<std::string> caretaker;
+    Originator<std::string> originator;
+};
+
+}
+}
+
+```
+## Generated UML diagrams
+![t00026_class](./t00026_class.png "Template memento pattern")