Console.md

Schrödinger's cat console application

This example demonstrates the creation of a simple console application in the pure DI paradigm using the Pure.DI code generator. All code is in one file for easy perception:

using Pure.DI;
using static Pure.DI.Lifetime;

namespace Sample;

// Let's create an abstraction

public interface IBox<out T>
{
    T Content { get; }
}

public interface ICat
{
    State State { get; }
}

public enum State
{
    Alive,
    Dead
}

// Here is our implementation

public class CardboardBox<T>(T content) : IBox<T>
{
    public T Content { get; } = content;

    public override string ToString() => $"[{Content}]";
}

public class ShroedingersCat(Lazy<State> superposition) : ICat
{
    // The decoherence of the superposition
    // at the time of observation via an irreversible process
    public State State => superposition.Value;

    public override string ToString() => $"{State} cat";
}

// Let's glue all together

internal partial class Composition
{
    // In fact, this code is never run, and the method can have any name or be a constructor, for example,
    // and can be in any part of the compiled code because this is just a hint to set up an object graph.
    // Here the setup is part of the generated class, just as an example.
    void Setup() => DI.Setup()
        // Models a random subatomic event that may or may not occur
        .Bind().As(Singleton).To<Random>()
        // Represents a quantum superposition of 2 states: Alive or Dead
        .Bind().To((Random random) => (State)random.Next(2))
        // Represents schrodinger's cat
        .Bind().To<ShroedingersCat>()
        // Represents a cardboard box with any content
        .Bind().To<CardboardBox<TT>>()
        // Composition Root
        .Root<Program>("Root");
}

// Time to open boxes!

public class Program(IBox<ICat> box)
{
    // Composition Root, a single place in an application
    // where the composition of the object graphs for an application take place
    public static void Main() => new Composition().Root.Run();

    private void Run() => Console.WriteLine(box);
}

The project file looks like this:

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <OutputType>Exe</OutputType>
        <TargetFramework>net9.0</TargetFramework>
    </PropertyGroup>

    <ItemGroup>
        <PackageReference Include="Pure.DI" Version="2.1.41">
            <PrivateAssets>all</PrivateAssets>
            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
        </PackageReference>
    </ItemGroup>

</Project>

It contains an additional reference to the NuGet package:

Pure.DI		DI Source code generator