Arlecchino

Views are plain classes

A view implements three members and takes its dependencies through the constructor. Navigation keeps a history, so going back is free.

Routes that read like an enum

A source generator finds every view, command, store and widget in the project and writes ViewKind and the registration extensions for them.

One surface, two layouts

Surface is a double-buffered cell grid. Write down the screen with the flow API, or place things by coordinate on the canvas.

State that redraws itself

Atoms notify on change, computed values follow them, tracked atoms undo, and async atoms load on a background thread with a spinner.

Modals, a palette and a picker

Text, password, number, slider, toggle, choice, multi-choice, date, time and color modals come with the framework, along with a command palette and a file picker.

Nothing hardcoded in English

Every string the framework draws is a delegate an application can point at its own translations, including the ones inside the widgets.

Tested headlessly

ArlecchinoTestHost runs an application against a fake terminal and hands back the frame as plain text, so assertions are about what was drawn.

Ready for native AOT

The packages are annotated for trimming and published with IsAotCompatible, and CI draws a frame from a native build on every push.

The shortest application

using MyApp.Navigation;   // where the generator puts ViewKind and AddGeneratedViews

var builder = Host.CreateApplicationBuilder(args);

builder.Services
    .AddArlecchino(options => options.MinimumWidth = 60)
    .AddGeneratedViews()
    .AddGeneratedStores()
    .AddGeneratedCommands()
    .StartAt(ViewKind.Default);

await builder.Build().RunAsync();

The first view

public class DefaultView : IArlecchinoView
{
    private readonly Surface _surface;

    public DefaultView(Surface surface) => _surface = surface;

    public void Draw()
    {
        _surface.AppendLine("hello", Theme.Header, Align.Center);
    }

    public ViewRoute Handle(ConsoleKeyInfo key) =>
        key.Key == ConsoleKey.A ? ViewKind.About : ViewRoute.None;

    public (string Key, string Description)[] Hints() => [("a", "about")];
}

What it looks like

Arlecchino.Commander is a file manager built on the framework: two panels over local disks, SFTP and FTP, tabs, leader keys, a command line under the panels, a walk that searches names and the text inside files, copies that run in the background and report themselves, and a palette that reaches all of it by name.