Added option style to plantuml config section

src/common/model/diagram_element.h

@@ -93,16 +93,16 @@ public:
     void set_name(const std::string &name) { name_ = name; }
 
     /**
-     * Return diagram's name.
+     * Return diagram element name.
      *
-     * @return Diagram's name.
+     * @return Diagram element name.
      */
     std::string name() const { return name_; }
 
     /**
-     * Return the type name of the diagram.
+     * Return the type name of the diagram element.
      *
-     * @return Diagrams type name.
+     * @return Diagrams element type name.
      */
     virtual std::string type_name() const { return "__undefined__"; };
 

src/common/model/stylable_element.cc

@@ -22,6 +22,6 @@ namespace clanguml::common::model {
 
 void stylable_element::set_style(const std::string &style) { style_ = style; }
 
-std::string stylable_element::style() const { return style_; }
+std::optional<std::string> stylable_element::style() const { return style_; }
 
 }

src/common/model/stylable_element.h

@@ -17,6 +17,7 @@
  */
 #pragma once
 
+#include <optional>
 #include <string>
 
 namespace clanguml::common::model {
@@ -40,10 +41,10 @@ public:
      *
      * @return Style specification
      */
-    std::string style() const;
+    std::optional<std::string> style() const;
 
 private:
-    std::string style_;
+    std::optional<std::string> style_;
 };
 
 } // namespace clanguml::common::model