References

Official Documentation

LanguageExt

• GitHub: https://github.com/louthy/language-ext
• Documentation: https://languageext.readthedocs.io/
• NuGet: https://www.nuget.org/packages/LanguageExt.Core

Ardalis.SmartEnum

• GitHub: https://github.com/ardalis/SmartEnum
• NuGet: https://www.nuget.org/packages/Ardalis.SmartEnum

ArchUnitNET

• GitHub: https://github.com/TNG/ArchUnitNET
• NuGet: https://www.nuget.org/packages/TngTech.ArchUnitNET.xUnit

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References

Domain-Driven Design

• Title: Domain-Driven Design: Tackling Complexity in the Heart of Software
• Author: Eric Evans
• Published: Addison-Wesley, 2003
• Key Content: Original definitions of value objects, entities, and aggregates

Implementing Domain-Driven Design

• Title: Implementing Domain-Driven Design
• Author: Vaughn Vernon
• Published: Addison-Wesley, 2013
• Key Content: DDD practical implementation patterns, advanced value objects

Functional Programming in C#

• Title: Functional Programming in C#: How to write better C# code
• Author: Enrico Buonanno
• Published: Manning, 2022 (2nd Edition)
• Key Content: Option, Either, Railway Oriented Programming

Domain Modeling Made Functional

• Title: Domain Modeling Made Functional
• Author: Scott Wlaschin
• Published: Pragmatic Bookshelf, 2018
• Key Content: Functional DDD, type-driven design

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Online Resources

Blogs & Articles

Railway Oriented Programming

• https://fsharpforfunandprofit.com/rop/
• Scott Wlaschin’s error handling pattern series

Value Object Patterns

• https://enterprisecraftsmanship.com/posts/value-objects-explained/
• Vladimir Khorikov’s in-depth analysis of value objects

Always Valid Domain Model

• https://enterprisecraftsmanship.com/posts/always-valid-domain-model/
• Designing always-valid domain models

Videos

NDC Conferences

• “Functional Programming in C#” - Enrico Buonanno
• “Domain Modeling Made Functional” - Scott Wlaschin

Pluralsight

• “Domain-Driven Design Fundamentals”
• “Applying Functional Principles in C#“

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Related Libraries

Functional Programming

Libraries that support functional patterns in C#.

Library	Description	NuGet
LanguageExt.Core	Core functional types	✅
LanguageExt.Sys	Side effect management	✅
CSharpFunctionalExtensions	Lightweight Result type	✅
Optional	Simple Option implementation	✅

DDD & Clean Architecture

Libraries used for Domain-Driven Design and Clean Architecture implementation.

Library	Description	NuGet
MediatR	CQRS/Mediator pattern	✅
Ardalis.Specification	Repository pattern	✅
FluentValidation	Validation library	✅
ErrorOr	Error/Result type	✅

Testing

Libraries used for writing tests and architecture verification.

Library	Description	NuGet
ArchUnitNET	Architecture tests	✅
Shouldly	Assertion library	✅
xUnit	Test framework	✅
NSubstitute	Mock library	✅

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Functorium Project Reference

Source Code Location

Src/Functorium/Domains/ValueObjects/
├── IValueObject.cs                    # Marker interface
├── AbstractValueObject.cs             # Base abstract class
├── ValueObject.cs                     # Composite value object
├── SimpleValueObject.cs               # Single value wrapper
├── ComparableValueObject.cs           # Comparable composite
├── ComparableSimpleValueObject.cs     # Comparable single
└── Validations/
    ├── ValidationApplyExtensions.cs   # Tuple Apply (internal .As() handling)
    └── Typed/
        ├── ValidationRules.cs         # Type-safe validation entry point
        ├── TypedValidation.cs         # Type information wrapper
        └── TypedValidationExtensions.*.cs  # Then chaining methods

Src/Functorium/Domains/Errors/
├── DomainError.cs                     # DomainError.For<T>() helper
└── DomainErrorType.cs                 # Error type sealed record hierarchy

CQRS Integration

Src/Functorium/Applications/Cqrs/
├── FinExtensions.cs                   # Fin<T> → Response conversion
└── ValidationExtensions.cs            # Validation → Response conversion

Tutorial Projects

Docs.Site/src/content/docs/tutorials/functional-valueobject/
├── Part1-ValueObject-Concepts/        # Part 1: Understanding Concepts (16)
├── Part2-Validation-Patterns/         # Part 2: Validation Patterns (6)
├── Part3-ValueObject-Patterns/        # Part 3: Value Object Patterns (9)
├── Part4-Practical-Guide/             # Part 4: Practical Guide (4)
└── Part5-Domain-Examples/             # Part 5: Domain Examples (4)

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Recommended Learning Order

Beginners (Functional Introduction)

1. Quick Start in the official LanguageExt documentation
2. “Functional Programming in C#” book, chapters 1-5
3. This tutorial, Part 1 (Chapters 1-6)

Intermediate (Practical Application)

1. “Domain Modeling Made Functional” book
2. This tutorial, Parts 2-3
3. Railway Oriented Programming blog

Advanced (Architecture Design)

1. “Implementing Domain-Driven Design” book
2. This tutorial, Parts 4-5
3. Writing architecture tests with ArchUnitNET

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Community

GitHub Discussions

• LanguageExt: https://github.com/louthy/language-ext/discussions
• Functorium: https://github.com/hhko/Functorium/discussions

Stack Overflow Tags

• languageext
• domain-driven-design
• value-objects
• functional-programming

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