Tutorial: Getting started

Build a small data model and observe how values behave. You will create a point, copy it with one change, and compare the original with another point.

Prerequisites

Complete installation first. You need the .NET 10 SDK and the published G# project templates.

1. Scaffold a console app

dotnet new gsharp-console -n PointApp
cd PointApp

2. Inspect the project file

Open PointApp.gsproj. The template selects Gsharp.NET.Sdk, declares an executable, and targets net10.0. The SDK includes .gs files automatically; you do not need to list Program.gs manually.

That is enough project configuration for this tutorial. Projects and packages explains how to organize larger programs.

3. Replace the program

Replace Program.gs with the checked-in samples/WebsiteData.gs example:

Program.gs

package Website.Data

import System

data class Point(X int32, Y int32)

let origin = Point(0, 0)
let moved = origin with{X = 3}

Console.WriteLine("(${moved.X}, ${moved.Y})")
Console.WriteLine(origin == Point(0, 0))

data class declares a reference-typed data model with structural equality. The with expression creates a copy with a changed X; it does not modify origin.

String interpolation puts the coordinate values into the printed message. The second line compares points by their data rather than requiring them to be the same object.

4. Build and run

dotnet run

Expected output:

(3, 0)
True

Try changing the copied X value or adding a Y update. The first output changes; the comparison of the unchanged original still prints True.

5. Try direct compiler output

Direct compiler invocation is optional. If you already have a source-built gsc, you can emit this same file with /out and run the resulting assembly. The quickstart shows the commands; ordinary application work can stay with the SDK.

Next steps

Continue with Projects and packages, or explore data and types for value types, nullable data, and collections.