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PromptEditor

PromptEditor is a prompt-style text editor built on top of the TextEditorBase / TextEditorCore infrastructure.

It is designed for REPLs and terminal prompts where you want:

  • a prompt prefix (markup),
  • multi-line editing,
  • completion (ghost + popup/cycling),
  • prompt-oriented accept/cancel actions,
  • optional syntax highlighting.

PromptEditor

Basic usage

var command = new State<string?>(string.Empty);

var editor = new PromptEditor()
    .Text(command)
    .PromptMarkup("[primary]demo[/] [muted]>[/] ")
    .Placeholder("Type a command… (Tab completes)");

Enter vs Ctrl+J (new line)

By default:

  • Enter accepts
  • Ctrl+J inserts a newline (\n)

You can swap these behaviors:

new PromptEditor()
    .EnterMode(PromptEditorEnterMode.EnterInsertsNewLine);

Syntax highlighting

PromptEditor supports lightweight, pluggable syntax highlighting via a delegate that produces style runs:

new PromptEditor()
    .Highlighter((in PromptEditorHighlightRequest request, List<StyledRun> runs) =>
    {
        // Use request.Snapshot and add StyledRun(start, length, style) entries.
        // request.CaretIndex / request.Selection* are provided for caret-aware highlighting.
    });

Completion

Completion is pluggable via CompletionHandler:

new PromptEditor()
    .CompletionPresentation(PromptEditorCompletionPresentation.PopupList)
    .CompletionHandler(request =>
    {
        // Compute candidates for request.Snapshot at request.CaretIndex...
        return new PromptEditorCompletion(
            Handled: true,
            Candidates: new[] { "help", "clear", "exit" },
            ReplaceStart: 0,
            ReplaceLength: request.CaretIndex,
            GhostText: "elp");
    });

Default behavior:

  • Tab requests completion (unless AcceptTab=true).
  • Esc cancels completion (or cancels the prompt if no completion UI is active).

Prompt prefix

PromptEditor renders the prompt prefix in a dedicated left column:

  • PromptMarkup is rendered on the first visual row
  • ContinuationPromptMarkup is rendered for continuation rows

If ContinuationPromptMarkup is empty, the control keeps the column width but does not draw text.

Prompt as a visual

For richer prompts (icons, spinners, widgets…), you can provide a visual prompt:

new PromptEditor()
    .Prompt(new HStack(
        new Spinner().MinWidth(1),
        new Markup("[primary]demo[/] [muted]>[/] ")));

When Prompt is set, it takes precedence over PromptMarkup on the first visual row. Continuation rows still use ContinuationPromptMarkup (or indentation if empty).

Commands (CommandBar)

PromptEditor registers prompt-specific commands so a CommandBar can surface shortcuts:

  • PromptEditor.Accept
  • PromptEditor.Cancel
  • PromptEditor.InsertNewLine
  • PromptEditor.Complete
  • PromptEditor.HistoryPrevious / PromptEditor.HistoryNext

It also inherits TextEditor.* commands from TextEditorBase (undo/redo/copy/paste/select-all, etc.).

Defaults

  • Default alignment: HorizontalAlignment = Align.Stretch, VerticalAlignment = Align.Stretch

See also