This directory contains detailed references for 14 architectural patterns used in software design. Each pattern document includes the problem it solves, the solution approach, when to use it, when to avoid it, pseudocode, and runnable code examples in multiple languages.

Patterns

#	Pattern	File	Summary
1	Repository	`repository.md`	Abstract data access behind a collection-like interface
2	Unit of Work	`unit-of-work.md`	Track and commit changes atomically
3	Service Layer	`service-layer.md`	Define application boundaries with a service API
4	MVC	`mvc.md`	Model-View-Controller separation
5	MVVM	`mvvm.md`	Model-View-ViewModel with data binding
6	MVP	`mvp.md`	Model-View-Presenter with passive view
7	CQRS	`cqrs.md`	Separate read and write models
8	Event Sourcing	`event-sourcing.md`	Store state as a sequence of events
9	Specification	`specification.md`	Composable business rules as objects
10	Hexagonal / Ports & Adapters	`hexagonal.md`	Isolate core logic from external concerns
11	Clean Architecture	`clean-architecture.md`	Enforce the dependency rule across concentric layers
12	Microkernel	`microkernel.md`	Minimal core with plug-in extensions
13	Layered Architecture	`layered.md`	Horizontal layer separation
14	Pipe and Filter	`pipe-and-filter.md`	Chained transformation stages

How to Use These References

Each file follows a consistent structure:

Problem - What design challenge the pattern addresses
Solution - How the pattern solves it
When to Use - Scenarios where this pattern excels
When to Avoid - Scenarios where this pattern adds unnecessary complexity
Pseudocode - Language-agnostic algorithm sketch
Code Examples - Runnable implementations in Python plus Go or JavaScript

Categorization

Data Access Patterns

Repository, Unit of Work

Application Structure Patterns

Service Layer, Layered Architecture, Clean Architecture, Hexagonal

UI Separation Patterns

MVC, MVVM, MVP

Domain Logic Patterns

CQRS, Event Sourcing, Specification

System Composition Patterns

Microkernel, Pipe and Filter