Rud Merriam | A Journey into Non-Virtual Polymorphism 2 Who Doesn’t Recognize This?? 1990 Borland Turbo C++Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 3 Background ● Experience – Medium.com (https://medium.com/@rudmerriam)Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 4 Polymorphism ● Greek: “many forms” (Obligatory statement) ● The use of a single variableCppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 5 Polymorphic Variables ● Base class pointer to derived class – Virtual functions are not bad! ● Standard Template Library

carePhoto by Tech Nick on unsplashSimple benchmark class Base { public: int concrete() const; virtual int virt() const; }; void benchmark(Base *b, size_t num_iterations) { auto start = Clock::now(); virt_duration = end-start;There are interesting technical details and surprising conclusions that virtual functions can be actually faster. Since CPU architectures are mentioned, I'd expect to see deep nt-vs-inheritance-vs-other- ways-performanceDoes it even matter?Conclusions ● The notion that “virtual functions are slower” is flat out wrong. ○ Which is not to say they are faster ○ Some of the suggested

name, const NodeConfig& config) : SyncActionNode(name, config) {} // You must override this virtual function NodeStatus tick() override { std::cout << "Type: [ApproachEnemy]. Instance:" <<

@foonathan Express your expectations CppCon 2023-10-03 11JSON DOM parser Jonathan Müller — @foonathan Express your expectations CppCon 2023-10-03 12JSON DOM parser Idea: Represent a JSON value in C++. auto p 2023-10-03 16Problems with JSON DOM parsers json_value is stringly typed, Jonathan Müller — @foonathan Express your expectations CppCon 2023-10-03 17Problems with JSON DOM parsers json_value is stringly allocation, Jonathan Müller — @foonathan Express your expectations CppCon 2023-10-03 17Problems with JSON DOM parsers json_value is stringly typed, which requires dynamic memory allocation, manual error handling

. . . . . . . . . . . 1010 20.6 xml.dom —文档对象模型 API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1025 20.7 xml.dom.minidom —最小化的 DOM 实现 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1034 20.8 xml.dom.pulldom —支持构建部分 DOM 树 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039 20.9 xml.sax —支持 SAX2 解析器 . . . . . . . . . . . . . . . . . . . . . . . . . true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) subclass thereof. If object is not an object of the given type, the function always returns false

. . . . . . . . . . . 1010 20.6 xml.dom —文档对象模型 API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1025 20.7 xml.dom.minidom —最小化的 DOM 实现 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1034 20.8 xml.dom.pulldom —支持构建部分 DOM 树 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039 20.9 xml.sax —支持 SAX2 解析器 . . . . . . . . . . . . . . . . . . . . . . . . . true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) subclass thereof. If object is not an object of the given type, the function always returns false

. . . . . . . . . . 833 19.8 xml.dom —The Document Object Model API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 846 19.9 xml.dom.minidom —Minimal DOM implementation . . . . . . . . . . . . . . . . . . . . . . . . 856 19.10 xml.dom.pulldom —Support for building partial DOM trees . . . . . . . . . . . . . . . . . . . . 861 19.11 xml.sax —Support for SAX2 parsers . . . . . . . . . . true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) 12 Chapter 2. 内置函数 The Python Library Reference, 发布 2.7.18 subclass thereof. Also return true

. . . . . . . . . . 833 19.8 xml.dom —The Document Object Model API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 846 19.9 xml.dom.minidom —Minimal DOM implementation . . . . . . . . . . . . . . . . . . . . . . . . 856 19.10 xml.dom.pulldom —Support for building partial DOM trees . . . . . . . . . . . . . . . . . . . . 861 19.11 xml.sax —Support for SAX2 parsers . . . . . . . . . . true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) 12 Chapter 2. 内置函数 The Python Library Reference, 发布 2.7.18 subclass thereof. Also return true

. . . . . . . . . . 833 19.8 xml.dom —The Document Object Model API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 846 19.9 xml.dom.minidom —Minimal DOM implementation . . . . . . . . . . . . . . . . . . . . . . . . 856 19.10 xml.dom.pulldom —Support for building partial DOM trees . . . . . . . . . . . . . . . . . . . . 861 19.11 xml.sax —Support for SAX2 parsers . . . . . . . . . . true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual) 12 Chapter 2. 内置函数 The Python Library Reference, 发布 2.7.18 subclass thereof. Also return true

. . . . . . . . . . . 1000 21.6 xml.dom --- 文档对象模型 API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1015 21.7 xml.dom.minidom --- 最小化的 DOM 实现 . . . . . . . . . . . . . . . . . . . . . . . . . . 1024 21.8 xml.dom.pulldom --- 支持构建部分 DOM 树 . . . . . . . . . . . . . . . . . . . . . . . . . 1028 21.9 xml.sax --- 支持 SAX2 解析器 . . . . . . . . . . . . . . . . . . . . . . . . . . FILE_ATTRIBUTE_SPARSE_FILE stat.FILE_ATTRIBUTE_SYSTEM stat.FILE_ATTRIBUTE_TEMPORARY stat.FILE_ATTRIBUTE_VIRTUAL 3.5 新版功能. 11.5 filecmp --- 文件及目录的比较 源代码: Lib/filecmp.py filecmp 模块定义了用于比较文件及目录的函数，并且可以选取多种关于时间和准确性的折衷方案。对