code":"#include \r\n#include \r\n#include \r\n\r\nstruct IElement\r\n{\r\n\tvirtual const std::string& name() const = 0;\r\n\r\n\tvirtual void visit(std::function)> visitor) = 0;\r\n};\r\n\r\nclass Element : public IElement\r\n\t, public std::enable_shared_from_this\r\n{\r\n\tElement(const std::string& name) : name_(name) {}\r\n\r\npublic:\r\n\tstatic auto create(const std::string& name)\r\n\t{\r\n\t\treturn std::shared_ptr(new Element(name));\r\n\t}\r\n\r\n\tvoid visit(std::function)> visitor) override\r\n\t{\r\n\t\tvisitor(shared_from_this());\r\n\t}\r\n\r\n\tconst std::string& name() const override { return name_; }\r\n\r\nprivate:\r\n\tstd::string name_;\r\n};\r\n\r\nclass ElementList : public IElement\r\n\t, public std::enable_shared_from_this\r\n{\r\n\tElementList(const std::string& name) : name_(name) {}\r\n\r\npublic:\r\n\tstatic auto create(const std::string& name)\r\n\t{\r\n\t\treturn std::shared_ptr(new ElementList(name));\r\n\t}\r\n\r\n\tvoid visit(std::function)> visitor) override\r\n\t{\r\n\t visitor(shared_from_this());\r\n\t\tfor (auto element : elements_) element->visit(visitor);\r\n\t}\r\n\r\n\tvoid add(std::shared_ptr element)\r\n\t{\r\n\t\telements_.push_back(element);\r\n\t}\r\n\r\n\tconst std::string& name() const override { return name_; }\r\n\r\nprivate:\r\n\tstd::string name_;\r\n\tstd::list> elements_;\r\n};\r\n\r\nint main()\r\n{\r\n\tauto root = ElementList::create(\"root\");\r\n\tauto elements1 = ElementList::create(\"element list 1\");\r\n\tauto elements2 = ElementList::create(\"element list 2\");\r\n\r\n\telements1->add(Element::create(\"element 1-1\"));\r\n\telements1->add(Element::create(\"element 1-2\"));\r\n\telements2->add(Element::create(\"element 2-1\"));\r\n\telements2->add(Element::create(\"element 2-2\"));\r\n\r\n\troot->add(elements1);\r\n\troot->add(elements2);\r\n\troot->add(Element::create(\"element 3\"));\r\n\r\n\troot->visit([](auto&& element) {\r\n\t\tprintf(\"%s\\n\", element->name().c_str());\r\n\t});\r\n\r\n return 0;\r\n}","file_name":"main.cpp","active":1}]

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