Environment Setup

Required Prerequisites

1. .NET 10.0 SDK

# Check version
dotnet --version
# Expected output: 10.0.100

# Install (Windows)
winget install Microsoft.DotNet.SDK.10

# Install (macOS)
brew install --cask dotnet-sdk

# Install (Linux - Ubuntu)
sudo apt-get update && sudo apt-get install -y dotnet-sdk-10.0

2. IDE Setup

VS Code + C# Dev Kit

• Install the C# Dev Kit extension

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Project Setup

Create a New Project

# Create a new project
dotnet new console -n MyValueObjectProject

# Install the LanguageExt package
cd MyValueObjectProject
dotnet add package LanguageExt.Core

Basic using Statements

These are the basic using statements to use in your project:

using LanguageExt;
using LanguageExt.Common;
using static LanguageExt.Prelude;

GlobalUsings.cs (Optional)

You can manage using statements used throughout the project in a single place:

GlobalUsings.cs

global using LanguageExt;
global using LanguageExt.Common;
global using static LanguageExt.Prelude;

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Running Each Project

Run a Project

# Navigate to a specific project
cd Docs/tutorials/Functional-ValueObject/01-Concept/01-Basic-Divide/BasicDivide

# Run the project
dotnet run

Run Tests

# Navigate to the test project
cd Docs/tutorials/Functional-ValueObject/01-Concept/01-Basic-Divide/BasicDivide.Tests.Unit

# Run tests
dotnet test

Build the Entire Solution

# From the solution root
dotnet build

# Run all tests
dotnet test

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Project Structure

Each tutorial project has the following structure:

01-Basic-Divide/
├── BasicDivide/                    # Main project
│   ├── Program.cs                  # Main entry file
│   ├── MathOperations.cs           # Core logic
│   ├── BasicDivide.csproj          # Project file
│   └── README.md                   # Project description
│
└── BasicDivide.Tests.Unit/         # Test project
    ├── MathOperationsTests.cs      # Test file
    ├── BasicDivide.Tests.Unit.csproj
    └── README.md

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Running the First Example

If the environment setup is complete, try running the first example:

cd Docs/tutorials/Functional-ValueObject/01-Concept/01-Basic-Divide/BasicDivide
dotnet run

Expected Output

=== Basic Division Function ===

Normal case:
10 / 2 = 5

Exception case:
10 / 0 = System.DivideByZeroException: Attempted to divide by zero.

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Troubleshooting

If the .NET SDK Is Not Recognized

# Check the PATH environment variable
echo $PATH

# On Windows, add the following path to system environment variables
# C:\Program Files\dotnet

LanguageExt Package Installation Failure

# Check NuGet sources
dotnet nuget list source

# Add the official NuGet source
dotnet nuget add source https://api.nuget.org/v3/index.json -n nuget.org

IntelliSense Not Working in the IDE

1. Restart the IDE
2. Run dotnet restore
3. Delete the .vs or .vscode folder and restart

FAQ

Q1: Can I run this with a version other than .NET 10?

A: The tutorial projects are written targeting .NET 10.0 SDK. Some code may work on earlier versions, but since there are parts that use .NET 10-specific features such as file-based program execution, .NET 10.0 or later is recommended.

Q2: Do I have to create GlobalUsings.cs?

A: No. It is optional. Declaring using LanguageExt; etc. directly in each file works the same way. It is convenient when you want to reduce repetitive using statements across the entire project.

Q3: Which version of the LanguageExt package should I install?

A: Running dotnet add package LanguageExt.Core installs the latest stable version. Each tutorial project has a verified version specified in its .csproj file, so building the solution will automatically restore the correct version.

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Next Steps

The environment setup is complete. Now in Part 1, you will directly observe the problems with a basic division function and take the first step toward evolving it into a value object.

→ Chapter 1: Starting with Basic Division