Added template decorator pattern

docs/test_cases.md

@@ -25,6 +25,7 @@
  * [t00024](./test_cases/t00024.md) - Proxy pattern
  * [t00025](./test_cases/t00025.md) - Template proxy pattern
  * [t00026](./test_cases/t00026.md) - Template memento pattern
+ * [t00027](./test_cases/t00027.md) - Template decorator pattern
 ## Sequence diagrams
  * [t20001](./test_cases/t20001.md) - Basic sequence diagram
 ## Configuration diagrams

docs/test_cases/t00026.md

@@ -74,7 +74,6 @@ struct StringMemento {
     Caretaker<std::string> caretaker;
     Originator<std::string> originator;
 };
-
 }
 }
 

docs/test_cases/t00027.md

@@ -0,0 +1,79 @@
+# t00027 - Template decorator pattern
+## Config
+```yaml
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00027_class:
+    type: class
+    glob:
+      - ../../tests/t00027/t00027.cc
+    using_namespace:
+      - clanguml::t00027
+    include:
+      namespaces:
+        - clanguml::t00027
+
+```
+## Source code
+File t00027.cc
+```cpp
+#include <memory>
+#include <tuple>
+#include <type_traits>
+
+namespace clanguml {
+namespace t00027 {
+
+class Shape {
+public:
+    virtual void display() = 0;
+    virtual ~Shape() = default;
+};
+
+template <template <typename> class... T>
+class Line : public Shape, public T<Line<>>... {
+public:
+    void display() override
+    {
+        std::apply([](auto &&... x) { (x.display(), ...); },
+            std::forward_as_tuple(T<Line<>>()...));
+    }
+};
+
+template <template <typename> class... T>
+class Text : public Shape, public T<Text<>>... {
+public:
+    void display() override
+    {
+        std::apply([](auto &&... x) { (x.display(), ...); },
+            std::forward_as_tuple(T<Text<>>()...));
+    }
+};
+
+struct ShapeDecorator {
+    virtual void display() = 0;
+};
+
+template <typename T> class Color : public ShapeDecorator {
+public:
+    void display() override {}
+};
+
+template <typename T> class Weight : public ShapeDecorator {
+public:
+    void display() override {}
+};
+
+struct Window {
+    Line<Color, Weight> border;
+    Line<Color> divider;
+    Text<Color, Weight> title;
+    Text<Color> description;
+};
+}
+}
+
+```
+## Generated UML diagrams
+![t00027_class](./t00027_class.png "Template decorator pattern")