Archive for category: Patterns

ClassIdioms

Regular Types

January 29, 2023

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The concept of a regular type goes back to the creator of the Standard Template Library (STL) Alexander…

classes

The Rule of Zero, or Six

January 22, 2023

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The rule of zero, or six, is one of the advanced rules in modern C++. I wrote in my current book "C++…

GeneralIdioms

Argument-Dependent Lookup and the Hidden Friend Idiom

January 16, 2023

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Argument-Dependent Lookup (ADL), also known as Koenig Lookup, is a set of "magical" rules for the lookup…

GeneralIdioms

Partial Function Application

January 8, 2023

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Partial Function Application is a technique in which a function binds a few of its arguments and returns…

GeneralIdioms

The Copy-and-Swap Idiom

December 18, 2022

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An idiom is an architectural or design pattern implementation in a concrete programming language. Applying…

BehavioralPattern

The Template Method

December 4, 2022

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The Template Method is a behavioral design pattern. It defines a skeleton for an algorithm and is probably…

BehavioralPattern

The Visitor Pattern

November 27, 2022

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The Visitor Pattern encapsulates an operation executed on an object hierarchy as an object and enables…

BehavioralPattern

The Observer Pattern

November 20, 2022

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The Observer Pattern is a behavioral pattern from the book "Design Patterns: Elements of Reusable…

patterns

The Proxy Pattern

November 13, 2022

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The Proxy Pattern is probably the most influential design pattern for C++. The Proxy provides a placeholder…

BehavioralPattern

The Strategy Pattern

November 12, 2022

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The Strategy Pattern is a behavioral design pattern from the book Design Patterns: Elements of Reusable…

Latest news

std::executionNovember 18, 2024 - 9:03 am
std::execution, previously known as executors or Senders/Receivers, provides “a Standard C++ framework for managing asynchronous execution on generic execution resources“. (P2300R10) Side Note Change of plans. My original plan was to present the C++26 library after the core language. However, the implementation status of the library is not good enough. Therefore, I decided to continue […]
C++26 Core Language: Small ImprovementsNovember 4, 2024 - 8:34 am
There are more small improvements in the C++26 language, which you should know. static_assert extension First, here’s the syntax of static_assert in C++11: static_assert(compile time predicate, unevaluated string) With C++26, the string can be a user-defined type having the following properties: static_assert can now be used with a format string. Here’s a nice example from […]
Placeholders and Extended Character SetOctober 28, 2024 - 10:19 am
Placeholders are a nice way to highlight variables that are no longer needed. Additionally, the character set of C++26 will be extended. Placeholders Structured bindings are a C++17 feature that allows you to bind multiple variables to the elements of a structured object. The following program demonstrates using tuples and structured bindings to return and […]
Contracts in C++26October 21, 2024 - 9:54 am
Contracts allow you to specify preconditions, postconditions, and invariants for functions. Contracts should already be part of C++20 but were removed in the standard meeting in Cologne. Here is what Herb Sutter said about contracts on Sutter’s Mill: “contracts is the most impactful feature of C++20 so far, and arguably the most impactful feature we […]
Reflection in C++26: Determine the LayoutOctober 14, 2024 - 9:42 am
Thanks to reflection, you can determine the layout of types. My examples are based on the reflection proposal P2996R5. Class Layout The following program determines the class layout of a few members. // classLayout.cpp #include <experimental/meta> #include <iostream> #include <utility> #include <vector> #include <array> struct member_descriptor { std::size_t offset; std::size_t size; bool operator==(member_descriptor const&) const […]
Reflection in C++26: Metafunctions for Enums and ClassesOctober 7, 2024 - 1:53 pm
Today, I continue my journey through reflection in C++26 and play with enums and classes. The names of the metafunctions to access an Enum or a Class member are often identical. Access the Members of an Enum The following program is based on one by Daveed Vandevoorde. Daveed is one of the fathers of reflection, […]