Design Patterns Hub: Creational, Structural, and Behavioral Software Patterns

Design patterns are formalized best practices and reusable architectural templates that software engineers use to solve commonly recurring design problems in object-oriented and functional systems. First cataloged by the "Gang of Four" (GoF), design patterns establish a shared vocabulary for developers and promote loose coupling, high cohesion, and maintainable software architectures.

This hub organizes creational, structural, and behavioral design patterns alongside modern idiomatic implementations.

1. Quick-Reference: Gang of Four (GoF) Pattern Categories

+-----------------------------------------------------------------------------------------+
|                               DESIGN PATTERN TAXONOMY                                   |
+-----------------------------------------------------------------------------------------+
| Category               | Core Purpose                      | Canonical Examples         |
+------------------------+-----------------------------------+----------------------------+
| Creational Patterns    | Object instantiation mechanics    | Factory Method, Builder,   |
|                        | and lifecycle decoupling          | Singleton, Abstract Factory|
| Structural Patterns    | Class and object composition into | Adapter, Decorator, Proxy, |
|                        | flexible larger structures        | Composite, Facade          |
| Behavioral Patterns    | Algorithms and assignment of      | Strategy, Observer, Command|
|                        | responsibilities between objects  | Visitor, Specification     |
+-----------------------------------------------------------------------------------------+

2. Core Deep Dives & Implementations

VisitorPattern: Decoupling algorithms and operations from complex object structures using double-dispatch.
SpecificationPattern: Composable boolean business rules and predicates for domain-driven design.
DependencyInjectionPatterns: Inversion of Control (IoC), dependency injection containers, and loose coupling.
SagaPattern: Distributed transaction choreography and compensating actions.