Interactive Prompts

Some commands need to ask the user questions, show progress, or handle long-running work gracefully. Repl provides a typed interaction channel for all of these.

Prompts

Inject IReplInteractionChannel (namespace Repl.Interaction) to ask the user questions mid-command:

using Repl.Interaction;

app.Map("add", async (IReplInteractionChannel ui, IContactStore store, CancellationToken ct) =>
{
    var name  = await ui.AskTextAsync("name",  "Full name:",     ct: ct);
    var email = await ui.AskTextAsync("email", "Email address:", ct: ct);

    var contact = store.Add(name, email);
    return Results.Success($"Added {contact.Name} (#{contact.Id}).");
});

In REPL mode this presents an interactive prompt. In CLI mode with --answer:* flags, answers are pre-filled deterministically.

Choice prompts

string[] options = ["admin", "editor", "viewer"];
var roleIndex = await ui.AskChoiceAsync("role", "Assign role:", options, ct: ct);
var role = options[roleIndex];

AskChoiceAsync returns the zero-based index of the selected item. AskMultiChoiceAsync returns IReadOnlyList<int>.

Confirmation

app.Map("delete {id:int}", async (int id, IReplInteractionChannel ui, IContactStore store, CancellationToken ct) =>
{
    var contact = store.Get(id);
    var confirmed = await ui.AskConfirmationAsync("confirm", $"Delete '{contact.Name}'? This cannot be undone.");

    if (!confirmed)
        return Results.Cancelled("Delete cancelled.");

    store.Delete(id);
    return Results.Success($"Deleted '{contact.Name}'.");
});

Progress

Each WriteProgressAsync call updates the progress display. Fire-and-forget style — no disposable to manage:

app.Map("import {file}", async (string file, IReplInteractionChannel ui, CancellationToken ct) =>
{
    var lines = await File.ReadAllLinesAsync(file, ct);

    for (int i = 0; i < lines.Length; i++)
    {
        ct.ThrowIfCancellationRequested();
        await ImportLine(lines[i], ct);
        await ui.WriteProgressAsync($"Importing…", (double)(i + 1) / lines.Length, ct);
    }

    return Results.Success($"Imported {lines.Length} records.");
});

Timeouts

app.Map("ping {host}", async (string host, CancellationToken ct) =>
{
    using var cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
    cts.CancelAfter(TimeSpan.FromSeconds(5));
    try
    {
        var reply = await Ping(host, cts.Token);
        return $"{host}: {reply.RoundtripTime}ms";
    }
    catch (OperationCanceledException)
    {
        return Results.Error("timeout", $"Ping to {host} timed out after 5s.");
    }
});

Deterministic automation with `--answer:*`

Pre-fill prompts by name from the command line — useful for scripts and tests without Repl.Testing:

myapp add --answer:name=Alice --answer:email=alice@example.com

This makes interactive commands fully scriptable without changing handler code. Prompt names match the first argument to AskTextAsync / AskChoiceAsync / AskConfirmationAsync.

Spectre.Console prompts

With Repl.Spectre, all prompts upgrade to rich Spectre.Console widgets automatically:

app.UseSpectreConsole();

No handler changes required. See the Spectre cookbook for details.