Breaking Dependencies: The SOLID Principles Klaus Iglberger, CppCon 2020 klaus.iglberger@gmx.de2 Klaus Iglberger C++ Trainer since 2016 Author of the C++ math library (Co-)Organizer The SOLID Principles Single-Responsibility Principle Open-Closed Principle Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Principle9 The SOLID Principles Single-Responsibility Inversion Principle Robert C. Martin Michael Feathers10 The SOLID Principles11 The SOLID Principles I will introduce the SOLID principles … … as guidelines not limited to OO programming … as general

code It compiles successfullyWhat is a test? 15 Acceptance Accessibility Active Ad-hoc Age Agile All-pairs Alpha API Application Assertion Automated Backward Compatibility Basis Path Benchmark familiar with the design principles ‣ Then consider trying TDDwrite a failing test write just the code to make the test pass refactor start end are we done?DesignThe SOLID principles Single Responsibility

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a number of proposals meant to make C++ «better for game developers». • We will look at the principles behind this effort, the output of this work and what this means for C++. » 7Things happening a number of proposals meant to make C++ «better for game developers». • We will look at the principles behind this effort, the output of this work and what this means for C++. » 8 The overall project will write the actual proposals 35What is P2966? • P2966 is a progress report • It state the principles on which that overall effort is based • It lists the paths explored so far, and tries to identify

Abstract “Regular” is not exactly a new concept. If we reflect back on STL and its design principles, as best described by Alexander Stepanov in his “Fundamentals of Generic Programming” paper, we ? This talk is not just about Regular types A moment to reflect back on STL and its design principles, as best described by Alexander Stepanov in his 1998 paper “Fundamentals of Generic Programming” go back to the roots... STL and Its Design Principles2023 Victor Ciura | @ciura_victor - Regular, Revisited 45 Slide Title STL and Its Design Principles youtube.com/watch?v=COuHLky7E2Q Talk presented

WHAT WE'LL COVER Preliminaries: motivations etc Case study: a nontrivial nonstandard algorithm Principles for algorithm design Some holes in the standard Ponters to further work 2 . 1ALGORITHMS: THE SOUL you have decided the parameter order according to principles, For binary functions, once you have decided the parameter order according to principles, name it as if it were infix (or member function/UFCS) because prefix "is_prefix_of" s 69 . 1EPILOGUE: FOUR ALGORITHMIC EPILOGUE: FOUR ALGORITHMIC PRINCIPLES PRINCIPLES The Law of Useful Return The Law of Separating Types The Law of Completeness The Law of Interface

First Principles Inspired by Descartes Applying Cartesian thought to concurrent systems, we see that first principles describe what the program does (what is programmed), while secondary principles such modifiers on them. "The conditions defined in secondary principles cannot be known without the first, whereas the reverse is not true." – Descartes, Principles of Philosophy (preface to French edition of 1647) and Implementation of Quantifiable Stack/Queue Live Demonstration Introducing Quantifiability Principles of Quantifiability 1. Methods are Conserved: Method calls are first class objects in the system

Josuttis – Addison-Wesley 2012 • Effective STL Scott Meyers – O'Reilly 2001 • Programming: Principles and Practice Using C++, Second Edition Bjarne Stroustrup – Addison-Wesley 2014 • cppreference containers 13CppCon 2021 – Back to Basics: Classic STL Copyright © 2021 Bob Steagall Original Design Principles • Comprehensive • Take all the best from APL, Lisp, Dylan, C library, USL Standard Components… types 14CppCon 2021 – Back to Basics: Classic STL Copyright © 2021 Bob Steagall Original Design Principles • Comprehensive • Take all the best from APL, Lisp, Dylan, C library, USL Standard Components…

Obstacle avoidance, collision response, priority deferment, etc…COMPOSABILITY FROM PRINCIPLES COMPOSABILITY FROM PRINCIPLES At the core, steering behaviours is based on the At the core, steering behaviours side-e�ectful behaviour world-switching Solutions Solutions:: use composable types apply SOLID principles avoid world-switchingTHE ZERO OBJECT THE ZERO OBJECT If writing this is If writing this is di�cult side-e�ectful behaviour world-switching Solutions Solutions:: use composable types apply SOLID principles avoid world-switching �nd a better abstraction?SECOND: PASSTHROUGH SECOND: PASSTHROUGH The second

conditions, signed/unsigned, etc. ▪ Not always identifying the problem ▪ Not much in the way of principles to apply ▪ Formation of SG23 - Safety and Security Kona 2022 Evening Session 38DIRECTION GROUP40 fully initialized (its value can’t change until assigned) ▪ Can reject in non-conforming modes ▪ Principles on applying it to current UB ▪ P2973 Erroneous behaviour for missing return from assignment ▪ (as a whole) safety experts ▪ Many of the solutions proposed are ad hoc ▪ We (desperately) need principles we can apply ▪ SYCL ▪ Subset of customers that have specific and critical requirements ▪ Formation