Program.cs

using System.ComponentModel;
using Repl;
using Repl.Parameters;

// Sample goal:
// - minimal CoreReplApp (no DI package)
// - simple contact commands + metadata attributes
var store = new ContactStore();
var commands = new ContactCommands(store);

var app = CoreReplApp.Create()
	.WithDescription("Core basics sample: minimal contacts REPL without DI dependencies.")
	.WithBanner("""
		  Try: list, add Alice alice@test.com, show 1, count
		  Also: error (exception handling), debug reset
		""");

app.Map("list", commands.List);
app.Map("add {name} {email:email}", commands.Add);
app.Map("show {id:int}", commands.Show);
app.Map("count", commands.Count);
app.Map("report period", commands.ReportPeriod);
app.Map("error", ErrorCommand);
app.Map("debug reset", commands.Reset);

return app.Run(args);

static object ErrorCommand() =>
	throw new ApplicationException("this is an error.");

file sealed class ContactCommands(ContactStore store)
{
	[Description("List all contacts.")]
	public List<Contact> List(SampleOutputOptions output)
	{
		_ = output;
		return [.. store.List()];
	}

	[Description("Add a new contact.")]
	public Contact Add(
		[Description("Contact full name")] string name,
		[Description("Email address")] string email)
		=> store.Add(name, email);

	[Description("Show one contact by id.")]
	public object Show(
		[Description("Contact numeric id")] int id,
		SampleOutputOptions output)
	{
		_ = output;
		return store.Find(id) is { } contact
			? contact
			: Results.NotFound($"Contact '{id}' was not found.");
	}

	[Description("Return the number of contacts.")]
	public object Count() => Results.Success("Contact count.", store.Count());

	[Description("Render a date-only reporting period from a temporal range literal.")]
	public string ReportPeriod(ReplDateRange period) =>
		$"Reporting from {period.From:yyyy-MM-dd} to {period.To:yyyy-MM-dd} ({store.Count()} contacts in memory).";

	[Description("Reset in-memory sample data.")]
	[Browsable(false)]
	public object Reset()
	{
		store.Reset();
		return Results.Success("Data reset complete.");
	}
}

[ReplOptionsGroup]
file sealed class SampleOutputOptions
{
	[ReplOption(Aliases = ["-f"])]
	[Description("Output format for this command.")]
	public string Format { get; set; } = "text";

	[ReplOption(ReverseAliases = ["--no-verbose"])]
	[Description("Enable verbose output.")]
	public bool Verbose { get; set; }
}