Adding upstream version 3.0.36.upstream/3.0.36upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

5 files changed, 1898 insertions, 0 deletions

diff --git a/src/prompt_toolkit/widgets/__init__.py b/src/prompt_toolkit/widgets/__init__.py
new file mode 100644
index 0000000..552d355
--- /dev/null
+++ b/src/prompt_toolkit/widgets/__init__.py
@@ -0,0 +1,60 @@
+"""
+Collection of reusable components for building full screen applications.
+These are higher level abstractions on top of the `prompt_toolkit.layout`
+module.
+
+Most of these widgets implement the ``__pt_container__`` method, which makes it
+possible to embed these in the layout like any other container.
+"""
+from .base import (
+    Box,
+    Button,
+    Checkbox,
+    CheckboxList,
+    Frame,
+    HorizontalLine,
+    Label,
+    ProgressBar,
+    RadioList,
+    Shadow,
+    TextArea,
+    VerticalLine,
+)
+from .dialogs import Dialog
+from .menus import MenuContainer, MenuItem
+from .toolbars import (
+    ArgToolbar,
+    CompletionsToolbar,
+    FormattedTextToolbar,
+    SearchToolbar,
+    SystemToolbar,
+    ValidationToolbar,
+)
+
+__all__ = [
+    # Base.
+    "TextArea",
+    "Label",
+    "Button",
+    "Frame",
+    "Shadow",
+    "Box",
+    "VerticalLine",
+    "HorizontalLine",
+    "CheckboxList",
+    "RadioList",
+    "Checkbox",
+    "ProgressBar",
+    # Toolbars.
+    "ArgToolbar",
+    "CompletionsToolbar",
+    "FormattedTextToolbar",
+    "SearchToolbar",
+    "SystemToolbar",
+    "ValidationToolbar",
+    # Dialogs.
+    "Dialog",
+    # Menus.
+    "MenuContainer",
+    "MenuItem",
+]
diff --git a/src/prompt_toolkit/widgets/base.py b/src/prompt_toolkit/widgets/base.py
new file mode 100644
index 0000000..38cbba0
--- /dev/null
+++ b/src/prompt_toolkit/widgets/base.py
@@ -0,0 +1,984 @@
+"""
+Collection of reusable components for building full screen applications.
+
+All of these widgets implement the ``__pt_container__`` method, which makes
+them usable in any situation where we are expecting a `prompt_toolkit`
+container object.
+
+.. warning::
+
+    At this point, the API for these widgets is considered unstable, and can
+    potentially change between minor releases (we try not too, but no
+    guarantees are made yet). The public API in
+    `prompt_toolkit.shortcuts.dialogs` on the other hand is considered stable.
+"""
+from functools import partial
+from typing import Callable, Generic, List, Optional, Sequence, Tuple, TypeVar, Union
+
+from prompt_toolkit.application.current import get_app
+from prompt_toolkit.auto_suggest import AutoSuggest, DynamicAutoSuggest
+from prompt_toolkit.buffer import Buffer, BufferAcceptHandler
+from prompt_toolkit.completion import Completer, DynamicCompleter
+from prompt_toolkit.document import Document
+from prompt_toolkit.filters import (
+    Condition,
+    FilterOrBool,
+    has_focus,
+    is_done,
+    is_true,
+    to_filter,
+)
+from prompt_toolkit.formatted_text import (
+    AnyFormattedText,
+    StyleAndTextTuples,
+    Template,
+    to_formatted_text,
+)
+from prompt_toolkit.formatted_text.utils import fragment_list_to_text
+from prompt_toolkit.history import History
+from prompt_toolkit.key_binding.key_bindings import KeyBindings
+from prompt_toolkit.key_binding.key_processor import KeyPressEvent
+from prompt_toolkit.keys import Keys
+from prompt_toolkit.layout.containers import (
+    AnyContainer,
+    ConditionalContainer,
+    Container,
+    DynamicContainer,
+    Float,
+    FloatContainer,
+    HSplit,
+    VSplit,
+    Window,
+    WindowAlign,
+)
+from prompt_toolkit.layout.controls import (
+    BufferControl,
+    FormattedTextControl,
+    GetLinePrefixCallable,
+)
+from prompt_toolkit.layout.dimension import AnyDimension
+from prompt_toolkit.layout.dimension import Dimension as D
+from prompt_toolkit.layout.dimension import to_dimension
+from prompt_toolkit.layout.margins import (
+    ConditionalMargin,
+    NumberedMargin,
+    ScrollbarMargin,
+)
+from prompt_toolkit.layout.processors import (
+    AppendAutoSuggestion,
+    BeforeInput,
+    ConditionalProcessor,
+    PasswordProcessor,
+    Processor,
+)
+from prompt_toolkit.lexers import DynamicLexer, Lexer
+from prompt_toolkit.mouse_events import MouseEvent, MouseEventType
+from prompt_toolkit.utils import get_cwidth
+from prompt_toolkit.validation import DynamicValidator, Validator
+
+from .toolbars import SearchToolbar
+
+__all__ = [
+    "TextArea",
+    "Label",
+    "Button",
+    "Frame",
+    "Shadow",
+    "Box",
+    "VerticalLine",
+    "HorizontalLine",
+    "RadioList",
+    "CheckboxList",
+    "Checkbox",  # backward compatibility
+    "ProgressBar",
+]
+
+E = KeyPressEvent
+
+
+class Border:
+    "Box drawing characters. (Thin)"
+    HORIZONTAL = "\u2500"
+    VERTICAL = "\u2502"
+    TOP_LEFT = "\u250c"
+    TOP_RIGHT = "\u2510"
+    BOTTOM_LEFT = "\u2514"
+    BOTTOM_RIGHT = "\u2518"
+
+
+class TextArea:
+    """
+    A simple input field.
+
+    This is a higher level abstraction on top of several other classes with
+    sane defaults.
+
+    This widget does have the most common options, but it does not intend to
+    cover every single use case. For more configurations options, you can
+    always build a text area manually, using a
+    :class:`~prompt_toolkit.buffer.Buffer`,
+    :class:`~prompt_toolkit.layout.BufferControl` and
+    :class:`~prompt_toolkit.layout.Window`.
+
+    Buffer attributes:
+
+    :param text: The initial text.
+    :param multiline: If True, allow multiline input.
+    :param completer: :class:`~prompt_toolkit.completion.Completer` instance
+        for auto completion.
+    :param complete_while_typing: Boolean.
+    :param accept_handler: Called when `Enter` is pressed (This should be a
+        callable that takes a buffer as input).
+    :param history: :class:`~prompt_toolkit.history.History` instance.
+    :param auto_suggest: :class:`~prompt_toolkit.auto_suggest.AutoSuggest`
+        instance for input suggestions.
+
+    BufferControl attributes:
+
+    :param password: When `True`, display using asterisks.
+    :param focusable: When `True`, allow this widget to receive the focus.
+    :param focus_on_click: When `True`, focus after mouse click.
+    :param input_processors: `None` or a list of
+        :class:`~prompt_toolkit.layout.Processor` objects.
+    :param validator: `None` or a :class:`~prompt_toolkit.validation.Validator`
+        object.
+
+    Window attributes:
+
+    :param lexer: :class:`~prompt_toolkit.lexers.Lexer` instance for syntax
+        highlighting.
+    :param wrap_lines: When `True`, don't scroll horizontally, but wrap lines.
+    :param width: Window width. (:class:`~prompt_toolkit.layout.Dimension` object.)
+    :param height: Window height. (:class:`~prompt_toolkit.layout.Dimension` object.)
+    :param scrollbar: When `True`, display a scroll bar.
+    :param style: A style string.
+    :param dont_extend_width: When `True`, don't take up more width then the
+                              preferred width reported by the control.
+    :param dont_extend_height: When `True`, don't take up more width then the
+                               preferred height reported by the control.
+    :param get_line_prefix: None or a callable that returns formatted text to
+        be inserted before a line. It takes a line number (int) and a
+        wrap_count and returns formatted text. This can be used for
+        implementation of line continuations, things like Vim "breakindent" and
+        so on.
+
+    Other attributes:
+
+    :param search_field: An optional `SearchToolbar` object.
+    """
+
+    def __init__(
+        self,
+        text: str = "",
+        multiline: FilterOrBool = True,
+        password: FilterOrBool = False,
+        lexer: Optional[Lexer] = None,
+        auto_suggest: Optional[AutoSuggest] = None,
+        completer: Optional[Completer] = None,
+        complete_while_typing: FilterOrBool = True,
+        validator: Optional[Validator] = None,
+        accept_handler: Optional[BufferAcceptHandler] = None,
+        history: Optional[History] = None,
+        focusable: FilterOrBool = True,
+        focus_on_click: FilterOrBool = False,
+        wrap_lines: FilterOrBool = True,
+        read_only: FilterOrBool = False,
+        width: AnyDimension = None,
+        height: AnyDimension = None,
+        dont_extend_height: FilterOrBool = False,
+        dont_extend_width: FilterOrBool = False,
+        line_numbers: bool = False,
+        get_line_prefix: Optional[GetLinePrefixCallable] = None,
+        scrollbar: bool = False,
+        style: str = "",
+        search_field: Optional[SearchToolbar] = None,
+        preview_search: FilterOrBool = True,
+        prompt: AnyFormattedText = "",
+        input_processors: Optional[List[Processor]] = None,
+        name: str = "",
+    ) -> None:
+
+        if search_field is None:
+            search_control = None
+        elif isinstance(search_field, SearchToolbar):
+            search_control = search_field.control
+
+        if input_processors is None:
+            input_processors = []
+
+        # Writeable attributes.
+        self.completer = completer
+        self.complete_while_typing = complete_while_typing
+        self.lexer = lexer
+        self.auto_suggest = auto_suggest
+        self.read_only = read_only
+        self.wrap_lines = wrap_lines
+        self.validator = validator
+
+        self.buffer = Buffer(
+            document=Document(text, 0),
+            multiline=multiline,
+            read_only=Condition(lambda: is_true(self.read_only)),
+            completer=DynamicCompleter(lambda: self.completer),
+            complete_while_typing=Condition(
+                lambda: is_true(self.complete_while_typing)
+            ),
+            validator=DynamicValidator(lambda: self.validator),
+            auto_suggest=DynamicAutoSuggest(lambda: self.auto_suggest),
+            accept_handler=accept_handler,
+            history=history,
+            name=name,
+        )
+
+        self.control = BufferControl(
+            buffer=self.buffer,
+            lexer=DynamicLexer(lambda: self.lexer),
+            input_processors=[
+                ConditionalProcessor(
+                    AppendAutoSuggestion(), has_focus(self.buffer) & ~is_done
+                ),
+                ConditionalProcessor(
+                    processor=PasswordProcessor(), filter=to_filter(password)
+                ),
+                BeforeInput(prompt, style="class:text-area.prompt"),
+            ]
+            + input_processors,
+            search_buffer_control=search_control,
+            preview_search=preview_search,
+            focusable=focusable,
+            focus_on_click=focus_on_click,
+        )
+
+        if multiline:
+            if scrollbar:
+                right_margins = [ScrollbarMargin(display_arrows=True)]
+            else:
+                right_margins = []
+            if line_numbers:
+                left_margins = [NumberedMargin()]
+            else:
+                left_margins = []
+        else:
+            height = D.exact(1)
+            left_margins = []
+            right_margins = []
+
+        style = "class:text-area " + style
+
+        # If no height was given, guarantee height of at least 1.
+        if height is None:
+            height = D(min=1)
+
+        self.window = Window(
+            height=height,
+            width=width,
+            dont_extend_height=dont_extend_height,
+            dont_extend_width=dont_extend_width,
+            content=self.control,
+            style=style,
+            wrap_lines=Condition(lambda: is_true(self.wrap_lines)),
+            left_margins=left_margins,
+            right_margins=right_margins,
+            get_line_prefix=get_line_prefix,
+        )
+
+    @property
+    def text(self) -> str:
+        """
+        The `Buffer` text.
+        """
+        return self.buffer.text
+
+    @text.setter
+    def text(self, value: str) -> None:
+        self.document = Document(value, 0)
+
+    @property
+    def document(self) -> Document:
+        """
+        The `Buffer` document (text + cursor position).
+        """
+        return self.buffer.document
+
+    @document.setter
+    def document(self, value: Document) -> None:
+        self.buffer.set_document(value, bypass_readonly=True)
+
+    @property
+    def accept_handler(self) -> Optional[BufferAcceptHandler]:
+        """
+        The accept handler. Called when the user accepts the input.
+        """
+        return self.buffer.accept_handler
+
+    @accept_handler.setter
+    def accept_handler(self, value: BufferAcceptHandler) -> None:
+        self.buffer.accept_handler = value
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class Label:
+    """
+    Widget that displays the given text. It is not editable or focusable.
+
+    :param text: Text to display. Can be multiline. All value types accepted by
+        :class:`prompt_toolkit.layout.FormattedTextControl` are allowed,
+        including a callable.
+    :param style: A style string.
+    :param width: When given, use this width, rather than calculating it from
+        the text size.
+    :param dont_extend_width: When `True`, don't take up more width than
+                              preferred, i.e. the length of the longest line of
+                              the text, or value of `width` parameter, if
+                              given. `True` by default
+    :param dont_extend_height: When `True`, don't take up more width than the
+                               preferred height, i.e. the number of lines of
+                               the text. `False` by default.
+    """
+
+    def __init__(
+        self,
+        text: AnyFormattedText,
+        style: str = "",
+        width: AnyDimension = None,
+        dont_extend_height: bool = True,
+        dont_extend_width: bool = False,
+        align: Union[WindowAlign, Callable[[], WindowAlign]] = WindowAlign.LEFT,
+        # There is no cursor navigation in a label, so it makes sense to always
+        # wrap lines by default.
+        wrap_lines: FilterOrBool = True,
+    ) -> None:
+
+        self.text = text
+
+        def get_width() -> AnyDimension:
+            if width is None:
+                text_fragments = to_formatted_text(self.text)
+                text = fragment_list_to_text(text_fragments)
+                if text:
+                    longest_line = max(get_cwidth(line) for line in text.splitlines())
+                else:
+                    return D(preferred=0)
+                return D(preferred=longest_line)
+            else:
+                return width
+
+        self.formatted_text_control = FormattedTextControl(text=lambda: self.text)
+
+        self.window = Window(
+            content=self.formatted_text_control,
+            width=get_width,
+            height=D(min=1),
+            style="class:label " + style,
+            dont_extend_height=dont_extend_height,
+            dont_extend_width=dont_extend_width,
+            align=align,
+            wrap_lines=wrap_lines,
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class Button:
+    """
+    Clickable button.
+
+    :param text: The caption for the button.
+    :param handler: `None` or callable. Called when the button is clicked. No
+        parameters are passed to this callable. Use for instance Python's
+        `functools.partial` to pass parameters to this callable if needed.
+    :param width: Width of the button.
+    """
+
+    def __init__(
+        self,
+        text: str,
+        handler: Optional[Callable[[], None]] = None,
+        width: int = 12,
+        left_symbol: str = "<",
+        right_symbol: str = ">",
+    ) -> None:
+
+        self.text = text
+        self.left_symbol = left_symbol
+        self.right_symbol = right_symbol
+        self.handler = handler
+        self.width = width
+        self.control = FormattedTextControl(
+            self._get_text_fragments,
+            key_bindings=self._get_key_bindings(),
+            focusable=True,
+        )
+
+        def get_style() -> str:
+            if get_app().layout.has_focus(self):
+                return "class:button.focused"
+            else:
+                return "class:button"
+
+        # Note: `dont_extend_width` is False, because we want to allow buttons
+        #       to take more space if the parent container provides more space.
+        #       Otherwise, we will also truncate the text.
+        #       Probably we need a better way here to adjust to width of the
+        #       button to the text.
+
+        self.window = Window(
+            self.control,
+            align=WindowAlign.CENTER,
+            height=1,
+            width=width,
+            style=get_style,
+            dont_extend_width=False,
+            dont_extend_height=True,
+        )
+
+    def _get_text_fragments(self) -> StyleAndTextTuples:
+        width = self.width - (
+            get_cwidth(self.left_symbol) + get_cwidth(self.right_symbol)
+        )
+        text = (f"{{:^{width}}}").format(self.text)
+
+        def handler(mouse_event: MouseEvent) -> None:
+            if (
+                self.handler is not None
+                and mouse_event.event_type == MouseEventType.MOUSE_UP
+            ):
+                self.handler()
+
+        return [
+            ("class:button.arrow", self.left_symbol, handler),
+            ("[SetCursorPosition]", ""),
+            ("class:button.text", text, handler),
+            ("class:button.arrow", self.right_symbol, handler),
+        ]
+
+    def _get_key_bindings(self) -> KeyBindings:
+        "Key bindings for the Button."
+        kb = KeyBindings()
+
+        @kb.add(" ")
+        @kb.add("enter")
+        def _(event: E) -> None:
+            if self.handler is not None:
+                self.handler()
+
+        return kb
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class Frame:
+    """
+    Draw a border around any container, optionally with a title text.
+
+    Changing the title and body of the frame is possible at runtime by
+    assigning to the `body` and `title` attributes of this class.
+
+    :param body: Another container object.
+    :param title: Text to be displayed in the top of the frame (can be formatted text).
+    :param style: Style string to be applied to this widget.
+    """
+
+    def __init__(
+        self,
+        body: AnyContainer,
+        title: AnyFormattedText = "",
+        style: str = "",
+        width: AnyDimension = None,
+        height: AnyDimension = None,
+        key_bindings: Optional[KeyBindings] = None,
+        modal: bool = False,
+    ) -> None:
+
+        self.title = title
+        self.body = body
+
+        fill = partial(Window, style="class:frame.border")
+        style = "class:frame " + style
+
+        top_row_with_title = VSplit(
+            [
+                fill(width=1, height=1, char=Border.TOP_LEFT),
+                fill(char=Border.HORIZONTAL),
+                fill(width=1, height=1, char="|"),
+                # Notice: we use `Template` here, because `self.title` can be an
+                # `HTML` object for instance.
+                Label(
+                    lambda: Template(" {} ").format(self.title),
+                    style="class:frame.label",
+                    dont_extend_width=True,
+                ),
+                fill(width=1, height=1, char="|"),
+                fill(char=Border.HORIZONTAL),
+                fill(width=1, height=1, char=Border.TOP_RIGHT),
+            ],
+            height=1,
+        )
+
+        top_row_without_title = VSplit(
+            [
+                fill(width=1, height=1, char=Border.TOP_LEFT),
+                fill(char=Border.HORIZONTAL),
+                fill(width=1, height=1, char=Border.TOP_RIGHT),
+            ],
+            height=1,
+        )
+
+        @Condition
+        def has_title() -> bool:
+            return bool(self.title)
+
+        self.container = HSplit(
+            [
+                ConditionalContainer(content=top_row_with_title, filter=has_title),
+                ConditionalContainer(content=top_row_without_title, filter=~has_title),
+                VSplit(
+                    [
+                        fill(width=1, char=Border.VERTICAL),
+                        DynamicContainer(lambda: self.body),
+                        fill(width=1, char=Border.VERTICAL),
+                        # Padding is required to make sure that if the content is
+                        # too small, the right frame border is still aligned.
+                    ],
+                    padding=0,
+                ),
+                VSplit(
+                    [
+                        fill(width=1, height=1, char=Border.BOTTOM_LEFT),
+                        fill(char=Border.HORIZONTAL),
+                        fill(width=1, height=1, char=Border.BOTTOM_RIGHT),
+                    ],
+                    # specifying height here will increase the rendering speed.
+                    height=1,
+                ),
+            ],
+            width=width,
+            height=height,
+            style=style,
+            key_bindings=key_bindings,
+            modal=modal,
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class Shadow:
+    """
+    Draw a shadow underneath/behind this container.
+    (This applies `class:shadow` the the cells under the shadow. The Style
+    should define the colors for the shadow.)
+
+    :param body: Another container object.
+    """
+
+    def __init__(self, body: AnyContainer) -> None:
+        self.container = FloatContainer(
+            content=body,
+            floats=[
+                Float(
+                    bottom=-1,
+                    height=1,
+                    left=1,
+                    right=-1,
+                    transparent=True,
+                    content=Window(style="class:shadow"),
+                ),
+                Float(
+                    bottom=-1,
+                    top=1,
+                    width=1,
+                    right=-1,
+                    transparent=True,
+                    content=Window(style="class:shadow"),
+                ),
+            ],
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class Box:
+    """
+    Add padding around a container.
+
+    This also makes sure that the parent can provide more space than required by
+    the child. This is very useful when wrapping a small element with a fixed
+    size into a ``VSplit`` or ``HSplit`` object. The ``HSplit`` and ``VSplit``
+    try to make sure to adapt respectively the width and height, possibly
+    shrinking other elements. Wrapping something in a ``Box`` makes it flexible.
+
+    :param body: Another container object.
+    :param padding: The margin to be used around the body. This can be
+        overridden by `padding_left`, padding_right`, `padding_top` and
+        `padding_bottom`.
+    :param style: A style string.
+    :param char: Character to be used for filling the space around the body.
+        (This is supposed to be a character with a terminal width of 1.)
+    """
+
+    def __init__(
+        self,
+        body: AnyContainer,
+        padding: AnyDimension = None,
+        padding_left: AnyDimension = None,
+        padding_right: AnyDimension = None,
+        padding_top: AnyDimension = None,
+        padding_bottom: AnyDimension = None,
+        width: AnyDimension = None,
+        height: AnyDimension = None,
+        style: str = "",
+        char: Union[None, str, Callable[[], str]] = None,
+        modal: bool = False,
+        key_bindings: Optional[KeyBindings] = None,
+    ) -> None:
+
+        if padding is None:
+            padding = D(preferred=0)
+
+        def get(value: AnyDimension) -> D:
+            if value is None:
+                value = padding
+            return to_dimension(value)
+
+        self.padding_left = get(padding_left)
+        self.padding_right = get(padding_right)
+        self.padding_top = get(padding_top)
+        self.padding_bottom = get(padding_bottom)
+        self.body = body
+
+        self.container = HSplit(
+            [
+                Window(height=self.padding_top, char=char),
+                VSplit(
+                    [
+                        Window(width=self.padding_left, char=char),
+                        body,
+                        Window(width=self.padding_right, char=char),
+                    ]
+                ),
+                Window(height=self.padding_bottom, char=char),
+            ],
+            width=width,
+            height=height,
+            style=style,
+            modal=modal,
+            key_bindings=None,
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+_T = TypeVar("_T")
+
+
+class _DialogList(Generic[_T]):
+    """
+    Common code for `RadioList` and `CheckboxList`.
+    """
+
+    open_character: str = ""
+    close_character: str = ""
+    container_style: str = ""
+    default_style: str = ""
+    selected_style: str = ""
+    checked_style: str = ""
+    multiple_selection: bool = False
+    show_scrollbar: bool = True
+
+    def __init__(
+        self,
+        values: Sequence[Tuple[_T, AnyFormattedText]],
+        default_values: Optional[Sequence[_T]] = None,
+    ) -> None:
+        assert len(values) > 0
+        default_values = default_values or []
+
+        self.values = values
+        # current_values will be used in multiple_selection,
+        # current_value will be used otherwise.
+        keys: List[_T] = [value for (value, _) in values]
+        self.current_values: List[_T] = [
+            value for value in default_values if value in keys
+        ]
+        self.current_value: _T = (
+            default_values[0]
+            if len(default_values) and default_values[0] in keys
+            else values[0][0]
+        )
+
+        # Cursor index: take first selected item or first item otherwise.
+        if len(self.current_values) > 0:
+            self._selected_index = keys.index(self.current_values[0])
+        else:
+            self._selected_index = 0
+
+        # Key bindings.
+        kb = KeyBindings()
+
+        @kb.add("up")
+        def _up(event: E) -> None:
+            self._selected_index = max(0, self._selected_index - 1)
+
+        @kb.add("down")
+        def _down(event: E) -> None:
+            self._selected_index = min(len(self.values) - 1, self._selected_index + 1)
+
+        @kb.add("pageup")
+        def _pageup(event: E) -> None:
+            w = event.app.layout.current_window
+            if w.render_info:
+                self._selected_index = max(
+                    0, self._selected_index - len(w.render_info.displayed_lines)
+                )
+
+        @kb.add("pagedown")
+        def _pagedown(event: E) -> None:
+            w = event.app.layout.current_window
+            if w.render_info:
+                self._selected_index = min(
+                    len(self.values) - 1,
+                    self._selected_index + len(w.render_info.displayed_lines),
+                )
+
+        @kb.add("enter")
+        @kb.add(" ")
+        def _click(event: E) -> None:
+            self._handle_enter()
+
+        @kb.add(Keys.Any)
+        def _find(event: E) -> None:
+            # We first check values after the selected value, then all values.
+            values = list(self.values)
+            for value in values[self._selected_index + 1 :] + values:
+                text = fragment_list_to_text(to_formatted_text(value[1])).lower()
+
+                if text.startswith(event.data.lower()):
+                    self._selected_index = self.values.index(value)
+                    return
+
+        # Control and window.
+        self.control = FormattedTextControl(
+            self._get_text_fragments, key_bindings=kb, focusable=True
+        )
+
+        self.window = Window(
+            content=self.control,
+            style=self.container_style,
+            right_margins=[
+                ConditionalMargin(
+                    margin=ScrollbarMargin(display_arrows=True),
+                    filter=Condition(lambda: self.show_scrollbar),
+                ),
+            ],
+            dont_extend_height=True,
+        )
+
+    def _handle_enter(self) -> None:
+        if self.multiple_selection:
+            val = self.values[self._selected_index][0]
+            if val in self.current_values:
+                self.current_values.remove(val)
+            else:
+                self.current_values.append(val)
+        else:
+            self.current_value = self.values[self._selected_index][0]
+
+    def _get_text_fragments(self) -> StyleAndTextTuples:
+        def mouse_handler(mouse_event: MouseEvent) -> None:
+            """
+            Set `_selected_index` and `current_value` according to the y
+            position of the mouse click event.
+            """
+            if mouse_event.event_type == MouseEventType.MOUSE_UP:
+                self._selected_index = mouse_event.position.y
+                self._handle_enter()
+
+        result: StyleAndTextTuples = []
+        for i, value in enumerate(self.values):
+            if self.multiple_selection:
+                checked = value[0] in self.current_values
+            else:
+                checked = value[0] == self.current_value
+            selected = i == self._selected_index
+
+            style = ""
+            if checked:
+                style += " " + self.checked_style
+            if selected:
+                style += " " + self.selected_style
+
+            result.append((style, self.open_character))
+
+            if selected:
+                result.append(("[SetCursorPosition]", ""))
+
+            if checked:
+                result.append((style, "*"))
+            else:
+                result.append((style, " "))
+
+            result.append((style, self.close_character))
+            result.append((self.default_style, " "))
+            result.extend(to_formatted_text(value[1], style=self.default_style))
+            result.append(("", "\n"))
+
+        # Add mouse handler to all fragments.
+        for i in range(len(result)):
+            result[i] = (result[i][0], result[i][1], mouse_handler)
+
+        result.pop()  # Remove last newline.
+        return result
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class RadioList(_DialogList[_T]):
+    """
+    List of radio buttons. Only one can be checked at the same time.
+
+    :param values: List of (value, label) tuples.
+    """
+
+    open_character = "("
+    close_character = ")"
+    container_style = "class:radio-list"
+    default_style = "class:radio"
+    selected_style = "class:radio-selected"
+    checked_style = "class:radio-checked"
+    multiple_selection = False
+
+    def __init__(
+        self,
+        values: Sequence[Tuple[_T, AnyFormattedText]],
+        default: Optional[_T] = None,
+    ) -> None:
+        if default is None:
+            default_values = None
+        else:
+            default_values = [default]
+
+        super().__init__(values, default_values=default_values)
+
+
+class CheckboxList(_DialogList[_T]):
+    """
+    List of checkbox buttons. Several can be checked at the same time.
+
+    :param values: List of (value, label) tuples.
+    """
+
+    open_character = "["
+    close_character = "]"
+    container_style = "class:checkbox-list"
+    default_style = "class:checkbox"
+    selected_style = "class:checkbox-selected"
+    checked_style = "class:checkbox-checked"
+    multiple_selection = True
+
+
+class Checkbox(CheckboxList[str]):
+    """Backward compatibility util: creates a 1-sized CheckboxList
+
+    :param text: the text
+    """
+
+    show_scrollbar = False
+
+    def __init__(self, text: AnyFormattedText = "", checked: bool = False) -> None:
+        values = [("value", text)]
+        super().__init__(values=values)
+        self.checked = checked
+
+    @property
+    def checked(self) -> bool:
+        return "value" in self.current_values
+
+    @checked.setter
+    def checked(self, value: bool) -> None:
+        if value:
+            self.current_values = ["value"]
+        else:
+            self.current_values = []
+
+
+class VerticalLine:
+    """
+    A simple vertical line with a width of 1.
+    """
+
+    def __init__(self) -> None:
+        self.window = Window(
+            char=Border.VERTICAL, style="class:line,vertical-line", width=1
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class HorizontalLine:
+    """
+    A simple horizontal line with a height of 1.
+    """
+
+    def __init__(self) -> None:
+        self.window = Window(
+            char=Border.HORIZONTAL, style="class:line,horizontal-line", height=1
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.window
+
+
+class ProgressBar:
+    def __init__(self) -> None:
+        self._percentage = 60
+
+        self.label = Label("60%")
+        self.container = FloatContainer(
+            content=Window(height=1),
+            floats=[
+                # We first draw the label, then the actual progress bar.  Right
+                # now, this is the only way to have the colors of the progress
+                # bar appear on top of the label. The problem is that our label
+                # can't be part of any `Window` below.
+                Float(content=self.label, top=0, bottom=0),
+                Float(
+                    left=0,
+                    top=0,
+                    right=0,
+                    bottom=0,
+                    content=VSplit(
+                        [
+                            Window(
+                                style="class:progress-bar.used",
+                                width=lambda: D(weight=int(self._percentage)),
+                            ),
+                            Window(
+                                style="class:progress-bar",
+                                width=lambda: D(weight=int(100 - self._percentage)),
+                            ),
+                        ]
+                    ),
+                ),
+            ],
+        )
+
+    @property
+    def percentage(self) -> int:
+        return self._percentage
+
+    @percentage.setter
+    def percentage(self, value: int) -> None:
+        self._percentage = value
+        self.label.text = f"{value}%"
+
+    def __pt_container__(self) -> Container:
+        return self.container
diff --git a/src/prompt_toolkit/widgets/dialogs.py b/src/prompt_toolkit/widgets/dialogs.py
new file mode 100644
index 0000000..920582b
--- /dev/null
+++ b/src/prompt_toolkit/widgets/dialogs.py
@@ -0,0 +1,106 @@
+"""
+Collection of reusable components for building full screen applications.
+"""
+from typing import Optional, Sequence, Union
+
+from prompt_toolkit.filters import has_completions, has_focus
+from prompt_toolkit.formatted_text import AnyFormattedText
+from prompt_toolkit.key_binding.bindings.focus import focus_next, focus_previous
+from prompt_toolkit.key_binding.key_bindings import KeyBindings
+from prompt_toolkit.layout.containers import (
+    AnyContainer,
+    DynamicContainer,
+    HSplit,
+    VSplit,
+)
+from prompt_toolkit.layout.dimension import AnyDimension
+from prompt_toolkit.layout.dimension import Dimension as D
+
+from .base import Box, Button, Frame, Shadow
+
+__all__ = [
+    "Dialog",
+]
+
+
+class Dialog:
+    """
+    Simple dialog window. This is the base for input dialogs, message dialogs
+    and confirmation dialogs.
+
+    Changing the title and body of the dialog is possible at runtime by
+    assigning to the `body` and `title` attributes of this class.
+
+    :param body: Child container object.
+    :param title: Text to be displayed in the heading of the dialog.
+    :param buttons: A list of `Button` widgets, displayed at the bottom.
+    """
+
+    def __init__(
+        self,
+        body: AnyContainer,
+        title: AnyFormattedText = "",
+        buttons: Optional[Sequence[Button]] = None,
+        modal: bool = True,
+        width: AnyDimension = None,
+        with_background: bool = False,
+    ) -> None:
+
+        self.body = body
+        self.title = title
+
+        buttons = buttons or []
+
+        # When a button is selected, handle left/right key bindings.
+        buttons_kb = KeyBindings()
+        if len(buttons) > 1:
+            first_selected = has_focus(buttons[0])
+            last_selected = has_focus(buttons[-1])
+
+            buttons_kb.add("left", filter=~first_selected)(focus_previous)
+            buttons_kb.add("right", filter=~last_selected)(focus_next)
+
+        frame_body: AnyContainer
+        if buttons:
+            frame_body = HSplit(
+                [
+                    # Add optional padding around the body.
+                    Box(
+                        body=DynamicContainer(lambda: self.body),
+                        padding=D(preferred=1, max=1),
+                        padding_bottom=0,
+                    ),
+                    # The buttons.
+                    Box(
+                        body=VSplit(buttons, padding=1, key_bindings=buttons_kb),
+                        height=D(min=1, max=3, preferred=3),
+                    ),
+                ]
+            )
+        else:
+            frame_body = body
+
+        # Key bindings for whole dialog.
+        kb = KeyBindings()
+        kb.add("tab", filter=~has_completions)(focus_next)
+        kb.add("s-tab", filter=~has_completions)(focus_previous)
+
+        frame = Shadow(
+            body=Frame(
+                title=lambda: self.title,
+                body=frame_body,
+                style="class:dialog.body",
+                width=(None if with_background is None else width),
+                key_bindings=kb,
+                modal=modal,
+            )
+        )
+
+        self.container: Union[Box, Shadow]
+        if with_background:
+            self.container = Box(body=frame, style="class:dialog", width=width)
+        else:
+            self.container = frame
+
+    def __pt_container__(self) -> AnyContainer:
+        return self.container
diff --git a/src/prompt_toolkit/widgets/menus.py b/src/prompt_toolkit/widgets/menus.py
new file mode 100644
index 0000000..6827ebe
--- /dev/null
+++ b/src/prompt_toolkit/widgets/menus.py
@@ -0,0 +1,374 @@
+from typing import Callable, Iterable, List, Optional, Sequence, Union
+
+from prompt_toolkit.application.current import get_app
+from prompt_toolkit.filters import Condition
+from prompt_toolkit.formatted_text.base import OneStyleAndTextTuple, StyleAndTextTuples
+from prompt_toolkit.key_binding.key_bindings import KeyBindings, KeyBindingsBase
+from prompt_toolkit.key_binding.key_processor import KeyPressEvent
+from prompt_toolkit.keys import Keys
+from prompt_toolkit.layout.containers import (
+    AnyContainer,
+    ConditionalContainer,
+    Container,
+    Float,
+    FloatContainer,
+    HSplit,
+    Window,
+)
+from prompt_toolkit.layout.controls import FormattedTextControl
+from prompt_toolkit.mouse_events import MouseEvent, MouseEventType
+from prompt_toolkit.utils import get_cwidth
+from prompt_toolkit.widgets import Shadow
+
+from .base import Border
+
+__all__ = [
+    "MenuContainer",
+    "MenuItem",
+]
+
+E = KeyPressEvent
+
+
+class MenuContainer:
+    """
+    :param floats: List of extra Float objects to display.
+    :param menu_items: List of `MenuItem` objects.
+    """
+
+    def __init__(
+        self,
+        body: AnyContainer,
+        menu_items: List["MenuItem"],
+        floats: Optional[List[Float]] = None,
+        key_bindings: Optional[KeyBindingsBase] = None,
+    ) -> None:
+
+        self.body = body
+        self.menu_items = menu_items
+        self.selected_menu = [0]
+
+        # Key bindings.
+        kb = KeyBindings()
+
+        @Condition
+        def in_main_menu() -> bool:
+            return len(self.selected_menu) == 1
+
+        @Condition
+        def in_sub_menu() -> bool:
+            return len(self.selected_menu) > 1
+
+        # Navigation through the main menu.
+
+        @kb.add("left", filter=in_main_menu)
+        def _left(event: E) -> None:
+            self.selected_menu[0] = max(0, self.selected_menu[0] - 1)
+
+        @kb.add("right", filter=in_main_menu)
+        def _right(event: E) -> None:
+            self.selected_menu[0] = min(
+                len(self.menu_items) - 1, self.selected_menu[0] + 1
+            )
+
+        @kb.add("down", filter=in_main_menu)
+        def _down(event: E) -> None:
+            self.selected_menu.append(0)
+
+        @kb.add("c-c", filter=in_main_menu)
+        @kb.add("c-g", filter=in_main_menu)
+        def _cancel(event: E) -> None:
+            "Leave menu."
+            event.app.layout.focus_last()
+
+        # Sub menu navigation.
+
+        @kb.add("left", filter=in_sub_menu)
+        @kb.add("c-g", filter=in_sub_menu)
+        @kb.add("c-c", filter=in_sub_menu)
+        def _back(event: E) -> None:
+            "Go back to parent menu."
+            if len(self.selected_menu) > 1:
+                self.selected_menu.pop()
+
+        @kb.add("right", filter=in_sub_menu)
+        def _submenu(event: E) -> None:
+            "go into sub menu."
+            if self._get_menu(len(self.selected_menu) - 1).children:
+                self.selected_menu.append(0)
+
+            # If This item does not have a sub menu. Go up in the parent menu.
+            elif (
+                len(self.selected_menu) == 2
+                and self.selected_menu[0] < len(self.menu_items) - 1
+            ):
+                self.selected_menu = [
+                    min(len(self.menu_items) - 1, self.selected_menu[0] + 1)
+                ]
+                if self.menu_items[self.selected_menu[0]].children:
+                    self.selected_menu.append(0)
+
+        @kb.add("up", filter=in_sub_menu)
+        def _up_in_submenu(event: E) -> None:
+            "Select previous (enabled) menu item or return to main menu."
+            # Look for previous enabled items in this sub menu.
+            menu = self._get_menu(len(self.selected_menu) - 2)
+            index = self.selected_menu[-1]
+
+            previous_indexes = [
+                i
+                for i, item in enumerate(menu.children)
+                if i < index and not item.disabled
+            ]
+
+            if previous_indexes:
+                self.selected_menu[-1] = previous_indexes[-1]
+            elif len(self.selected_menu) == 2:
+                # Return to main menu.
+                self.selected_menu.pop()
+
+        @kb.add("down", filter=in_sub_menu)
+        def _down_in_submenu(event: E) -> None:
+            "Select next (enabled) menu item."
+            menu = self._get_menu(len(self.selected_menu) - 2)
+            index = self.selected_menu[-1]
+
+            next_indexes = [
+                i
+                for i, item in enumerate(menu.children)
+                if i > index and not item.disabled
+            ]
+
+            if next_indexes:
+                self.selected_menu[-1] = next_indexes[0]
+
+        @kb.add("enter")
+        def _click(event: E) -> None:
+            "Click the selected menu item."
+            item = self._get_menu(len(self.selected_menu) - 1)
+            if item.handler:
+                event.app.layout.focus_last()
+                item.handler()
+
+        # Controls.
+        self.control = FormattedTextControl(
+            self._get_menu_fragments, key_bindings=kb, focusable=True, show_cursor=False
+        )
+
+        self.window = Window(height=1, content=self.control, style="class:menu-bar")
+
+        submenu = self._submenu(0)
+        submenu2 = self._submenu(1)
+        submenu3 = self._submenu(2)
+
+        @Condition
+        def has_focus() -> bool:
+            return get_app().layout.current_window == self.window
+
+        self.container = FloatContainer(
+            content=HSplit(
+                [
+                    # The titlebar.
+                    self.window,
+                    # The 'body', like defined above.
+                    body,
+                ]
+            ),
+            floats=[
+                Float(
+                    xcursor=True,
+                    ycursor=True,
+                    content=ConditionalContainer(
+                        content=Shadow(body=submenu), filter=has_focus
+                    ),
+                ),
+                Float(
+                    attach_to_window=submenu,
+                    xcursor=True,
+                    ycursor=True,
+                    allow_cover_cursor=True,
+                    content=ConditionalContainer(
+                        content=Shadow(body=submenu2),
+                        filter=has_focus
+                        & Condition(lambda: len(self.selected_menu) >= 1),
+                    ),
+                ),
+                Float(
+                    attach_to_window=submenu2,
+                    xcursor=True,
+                    ycursor=True,
+                    allow_cover_cursor=True,
+                    content=ConditionalContainer(
+                        content=Shadow(body=submenu3),
+                        filter=has_focus
+                        & Condition(lambda: len(self.selected_menu) >= 2),
+                    ),
+                ),
+                # --
+            ]
+            + (floats or []),
+            key_bindings=key_bindings,
+        )
+
+    def _get_menu(self, level: int) -> "MenuItem":
+        menu = self.menu_items[self.selected_menu[0]]
+
+        for i, index in enumerate(self.selected_menu[1:]):
+            if i < level:
+                try:
+                    menu = menu.children[index]
+                except IndexError:
+                    return MenuItem("debug")
+
+        return menu
+
+    def _get_menu_fragments(self) -> StyleAndTextTuples:
+        focused = get_app().layout.has_focus(self.window)
+
+        # This is called during the rendering. When we discover that this
+        # widget doesn't have the focus anymore. Reset menu state.
+        if not focused:
+            self.selected_menu = [0]
+
+        # Generate text fragments for the main menu.
+        def one_item(i: int, item: MenuItem) -> Iterable[OneStyleAndTextTuple]:
+            def mouse_handler(mouse_event: MouseEvent) -> None:
+                hover = mouse_event.event_type == MouseEventType.MOUSE_MOVE
+                if (
+                    mouse_event.event_type == MouseEventType.MOUSE_DOWN
+                    or hover
+                    and focused
+                ):
+                    # Toggle focus.
+                    app = get_app()
+                    if not hover:
+                        if app.layout.has_focus(self.window):
+                            if self.selected_menu == [i]:
+                                app.layout.focus_last()
+                        else:
+                            app.layout.focus(self.window)
+                    self.selected_menu = [i]
+
+            yield ("class:menu-bar", " ", mouse_handler)
+            if i == self.selected_menu[0] and focused:
+                yield ("[SetMenuPosition]", "", mouse_handler)
+                style = "class:menu-bar.selected-item"
+            else:
+                style = "class:menu-bar"
+            yield style, item.text, mouse_handler
+
+        result: StyleAndTextTuples = []
+        for i, item in enumerate(self.menu_items):
+            result.extend(one_item(i, item))
+
+        return result
+
+    def _submenu(self, level: int = 0) -> Window:
+        def get_text_fragments() -> StyleAndTextTuples:
+            result: StyleAndTextTuples = []
+            if level < len(self.selected_menu):
+                menu = self._get_menu(level)
+                if menu.children:
+                    result.append(("class:menu", Border.TOP_LEFT))
+                    result.append(("class:menu", Border.HORIZONTAL * (menu.width + 4)))
+                    result.append(("class:menu", Border.TOP_RIGHT))
+                    result.append(("", "\n"))
+                    try:
+                        selected_item = self.selected_menu[level + 1]
+                    except IndexError:
+                        selected_item = -1
+
+                    def one_item(
+                        i: int, item: MenuItem
+                    ) -> Iterable[OneStyleAndTextTuple]:
+                        def mouse_handler(mouse_event: MouseEvent) -> None:
+                            if item.disabled:
+                                # The arrow keys can't interact with menu items that are disabled.
+                                # The mouse shouldn't be able to either.
+                                return
+                            hover = mouse_event.event_type == MouseEventType.MOUSE_MOVE
+                            if (
+                                mouse_event.event_type == MouseEventType.MOUSE_UP
+                                or hover
+                            ):
+                                app = get_app()
+                                if not hover and item.handler:
+                                    app.layout.focus_last()
+                                    item.handler()
+                                else:
+                                    self.selected_menu = self.selected_menu[
+                                        : level + 1
+                                    ] + [i]
+
+                        if i == selected_item:
+                            yield ("[SetCursorPosition]", "")
+                            style = "class:menu-bar.selected-item"
+                        else:
+                            style = ""
+
+                        yield ("class:menu", Border.VERTICAL)
+                        if item.text == "-":
+                            yield (
+                                style + "class:menu-border",
+                                f"{Border.HORIZONTAL * (menu.width + 3)}",
+                                mouse_handler,
+                            )
+                        else:
+                            yield (
+                                style,
+                                f" {item.text}".ljust(menu.width + 3),
+                                mouse_handler,
+                            )
+
+                        if item.children:
+                            yield (style, ">", mouse_handler)
+                        else:
+                            yield (style, " ", mouse_handler)
+
+                        if i == selected_item:
+                            yield ("[SetMenuPosition]", "")
+                        yield ("class:menu", Border.VERTICAL)
+
+                        yield ("", "\n")
+
+                    for i, item in enumerate(menu.children):
+                        result.extend(one_item(i, item))
+
+                    result.append(("class:menu", Border.BOTTOM_LEFT))
+                    result.append(("class:menu", Border.HORIZONTAL * (menu.width + 4)))
+                    result.append(("class:menu", Border.BOTTOM_RIGHT))
+            return result
+
+        return Window(FormattedTextControl(get_text_fragments), style="class:menu")
+
+    @property
+    def floats(self) -> Optional[List[Float]]:
+        return self.container.floats
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class MenuItem:
+    def __init__(
+        self,
+        text: str = "",
+        handler: Optional[Callable[[], None]] = None,
+        children: Optional[List["MenuItem"]] = None,
+        shortcut: Optional[Sequence[Union[Keys, str]]] = None,
+        disabled: bool = False,
+    ) -> None:
+
+        self.text = text
+        self.handler = handler
+        self.children = children or []
+        self.shortcut = shortcut
+        self.disabled = disabled
+        self.selected_item = 0
+
+    @property
+    def width(self) -> int:
+        if self.children:
+            return max(get_cwidth(c.text) for c in self.children)
+        else:
+            return 0
diff --git a/src/prompt_toolkit/widgets/toolbars.py b/src/prompt_toolkit/widgets/toolbars.py
new file mode 100644
index 0000000..402ecaa
--- /dev/null
+++ b/src/prompt_toolkit/widgets/toolbars.py
@@ -0,0 +1,374 @@
+from typing import Any, Optional
+
+from prompt_toolkit.application.current import get_app
+from prompt_toolkit.buffer import Buffer
+from prompt_toolkit.enums import SYSTEM_BUFFER
+from prompt_toolkit.filters import (
+    Condition,
+    FilterOrBool,
+    emacs_mode,
+    has_arg,
+    has_completions,
+    has_focus,
+    has_validation_error,
+    to_filter,
+    vi_mode,
+    vi_navigation_mode,
+)
+from prompt_toolkit.formatted_text import (
+    AnyFormattedText,
+    StyleAndTextTuples,
+    fragment_list_len,
+    to_formatted_text,
+)
+from prompt_toolkit.key_binding.key_bindings import (
+    ConditionalKeyBindings,
+    KeyBindings,
+    KeyBindingsBase,
+    merge_key_bindings,
+)
+from prompt_toolkit.key_binding.key_processor import KeyPressEvent
+from prompt_toolkit.key_binding.vi_state import InputMode
+from prompt_toolkit.keys import Keys
+from prompt_toolkit.layout.containers import ConditionalContainer, Container, Window
+from prompt_toolkit.layout.controls import (
+    BufferControl,
+    FormattedTextControl,
+    SearchBufferControl,
+    UIContent,
+    UIControl,
+)
+from prompt_toolkit.layout.dimension import Dimension
+from prompt_toolkit.layout.processors import BeforeInput
+from prompt_toolkit.lexers import SimpleLexer
+from prompt_toolkit.search import SearchDirection
+
+__all__ = [
+    "ArgToolbar",
+    "CompletionsToolbar",
+    "FormattedTextToolbar",
+    "SearchToolbar",
+    "SystemToolbar",
+    "ValidationToolbar",
+]
+
+E = KeyPressEvent
+
+
+class FormattedTextToolbar(Window):
+    def __init__(self, text: AnyFormattedText, style: str = "", **kw: Any) -> None:
+        # Note: The style needs to be applied to the toolbar as a whole, not
+        #       just the `FormattedTextControl`.
+        super().__init__(
+            FormattedTextControl(text, **kw),
+            style=style,
+            dont_extend_height=True,
+            height=Dimension(min=1),
+        )
+
+
+class SystemToolbar:
+    """
+    Toolbar for a system prompt.
+
+    :param prompt: Prompt to be displayed to the user.
+    """
+
+    def __init__(
+        self,
+        prompt: AnyFormattedText = "Shell command: ",
+        enable_global_bindings: FilterOrBool = True,
+    ) -> None:
+
+        self.prompt = prompt
+        self.enable_global_bindings = to_filter(enable_global_bindings)
+
+        self.system_buffer = Buffer(name=SYSTEM_BUFFER)
+
+        self._bindings = self._build_key_bindings()
+
+        self.buffer_control = BufferControl(
+            buffer=self.system_buffer,
+            lexer=SimpleLexer(style="class:system-toolbar.text"),
+            input_processors=[
+                BeforeInput(lambda: self.prompt, style="class:system-toolbar")
+            ],
+            key_bindings=self._bindings,
+        )
+
+        self.window = Window(
+            self.buffer_control, height=1, style="class:system-toolbar"
+        )
+
+        self.container = ConditionalContainer(
+            content=self.window, filter=has_focus(self.system_buffer)
+        )
+
+    def _get_display_before_text(self) -> StyleAndTextTuples:
+        return [
+            ("class:system-toolbar", "Shell command: "),
+            ("class:system-toolbar.text", self.system_buffer.text),
+            ("", "\n"),
+        ]
+
+    def _build_key_bindings(self) -> KeyBindingsBase:
+        focused = has_focus(self.system_buffer)
+
+        # Emacs
+        emacs_bindings = KeyBindings()
+        handle = emacs_bindings.add
+
+        @handle("escape", filter=focused)
+        @handle("c-g", filter=focused)
+        @handle("c-c", filter=focused)
+        def _cancel(event: E) -> None:
+            "Hide system prompt."
+            self.system_buffer.reset()
+            event.app.layout.focus_last()
+
+        @handle("enter", filter=focused)
+        async def _accept(event: E) -> None:
+            "Run system command."
+            await event.app.run_system_command(
+                self.system_buffer.text,
+                display_before_text=self._get_display_before_text(),
+            )
+            self.system_buffer.reset(append_to_history=True)
+            event.app.layout.focus_last()
+
+        # Vi.
+        vi_bindings = KeyBindings()
+        handle = vi_bindings.add
+
+        @handle("escape", filter=focused)
+        @handle("c-c", filter=focused)
+        def _cancel_vi(event: E) -> None:
+            "Hide system prompt."
+            event.app.vi_state.input_mode = InputMode.NAVIGATION
+            self.system_buffer.reset()
+            event.app.layout.focus_last()
+
+        @handle("enter", filter=focused)
+        async def _accept_vi(event: E) -> None:
+            "Run system command."
+            event.app.vi_state.input_mode = InputMode.NAVIGATION
+            await event.app.run_system_command(
+                self.system_buffer.text,
+                display_before_text=self._get_display_before_text(),
+            )
+            self.system_buffer.reset(append_to_history=True)
+            event.app.layout.focus_last()
+
+        # Global bindings. (Listen to these bindings, even when this widget is
+        # not focussed.)
+        global_bindings = KeyBindings()
+        handle = global_bindings.add
+
+        @handle(Keys.Escape, "!", filter=~focused & emacs_mode, is_global=True)
+        def _focus_me(event: E) -> None:
+            "M-'!' will focus this user control."
+            event.app.layout.focus(self.window)
+
+        @handle("!", filter=~focused & vi_mode & vi_navigation_mode, is_global=True)
+        def _focus_me_vi(event: E) -> None:
+            "Focus."
+            event.app.vi_state.input_mode = InputMode.INSERT
+            event.app.layout.focus(self.window)
+
+        return merge_key_bindings(
+            [
+                ConditionalKeyBindings(emacs_bindings, emacs_mode),
+                ConditionalKeyBindings(vi_bindings, vi_mode),
+                ConditionalKeyBindings(global_bindings, self.enable_global_bindings),
+            ]
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class ArgToolbar:
+    def __init__(self) -> None:
+        def get_formatted_text() -> StyleAndTextTuples:
+            arg = get_app().key_processor.arg or ""
+            if arg == "-":
+                arg = "-1"
+
+            return [
+                ("class:arg-toolbar", "Repeat: "),
+                ("class:arg-toolbar.text", arg),
+            ]
+
+        self.window = Window(FormattedTextControl(get_formatted_text), height=1)
+
+        self.container = ConditionalContainer(content=self.window, filter=has_arg)
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class SearchToolbar:
+    """
+    :param vi_mode: Display '/' and '?' instead of I-search.
+    :param ignore_case: Search case insensitive.
+    """
+
+    def __init__(
+        self,
+        search_buffer: Optional[Buffer] = None,
+        vi_mode: bool = False,
+        text_if_not_searching: AnyFormattedText = "",
+        forward_search_prompt: AnyFormattedText = "I-search: ",
+        backward_search_prompt: AnyFormattedText = "I-search backward: ",
+        ignore_case: FilterOrBool = False,
+    ) -> None:
+
+        if search_buffer is None:
+            search_buffer = Buffer()
+
+        @Condition
+        def is_searching() -> bool:
+            return self.control in get_app().layout.search_links
+
+        def get_before_input() -> AnyFormattedText:
+            if not is_searching():
+                return text_if_not_searching
+            elif (
+                self.control.searcher_search_state.direction == SearchDirection.BACKWARD
+            ):
+                return "?" if vi_mode else backward_search_prompt
+            else:
+                return "/" if vi_mode else forward_search_prompt
+
+        self.search_buffer = search_buffer
+
+        self.control = SearchBufferControl(
+            buffer=search_buffer,
+            input_processors=[
+                BeforeInput(get_before_input, style="class:search-toolbar.prompt")
+            ],
+            lexer=SimpleLexer(style="class:search-toolbar.text"),
+            ignore_case=ignore_case,
+        )
+
+        self.container = ConditionalContainer(
+            content=Window(self.control, height=1, style="class:search-toolbar"),
+            filter=is_searching,
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class _CompletionsToolbarControl(UIControl):
+    def create_content(self, width: int, height: int) -> UIContent:
+        all_fragments: StyleAndTextTuples = []
+
+        complete_state = get_app().current_buffer.complete_state
+        if complete_state:
+            completions = complete_state.completions
+            index = complete_state.complete_index  # Can be None!
+
+            # Width of the completions without the left/right arrows in the margins.
+            content_width = width - 6
+
+            # Booleans indicating whether we stripped from the left/right
+            cut_left = False
+            cut_right = False
+
+            # Create Menu content.
+            fragments: StyleAndTextTuples = []
+
+            for i, c in enumerate(completions):
+                # When there is no more place for the next completion
+                if fragment_list_len(fragments) + len(c.display_text) >= content_width:
+                    # If the current one was not yet displayed, page to the next sequence.
+                    if i <= (index or 0):
+                        fragments = []
+                        cut_left = True
+                    # If the current one is visible, stop here.
+                    else:
+                        cut_right = True
+                        break
+
+                fragments.extend(
+                    to_formatted_text(
+                        c.display_text,
+                        style=(
+                            "class:completion-toolbar.completion.current"
+                            if i == index
+                            else "class:completion-toolbar.completion"
+                        ),
+                    )
+                )
+                fragments.append(("", " "))
+
+            # Extend/strip until the content width.
+            fragments.append(("", " " * (content_width - fragment_list_len(fragments))))
+            fragments = fragments[:content_width]
+
+            # Return fragments
+            all_fragments.append(("", " "))
+            all_fragments.append(
+                ("class:completion-toolbar.arrow", "<" if cut_left else " ")
+            )
+            all_fragments.append(("", " "))
+
+            all_fragments.extend(fragments)
+
+            all_fragments.append(("", " "))
+            all_fragments.append(
+                ("class:completion-toolbar.arrow", ">" if cut_right else " ")
+            )
+            all_fragments.append(("", " "))
+
+        def get_line(i: int) -> StyleAndTextTuples:
+            return all_fragments
+
+        return UIContent(get_line=get_line, line_count=1)
+
+
+class CompletionsToolbar:
+    def __init__(self) -> None:
+        self.container = ConditionalContainer(
+            content=Window(
+                _CompletionsToolbarControl(), height=1, style="class:completion-toolbar"
+            ),
+            filter=has_completions,
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container
+
+
+class ValidationToolbar:
+    def __init__(self, show_position: bool = False) -> None:
+        def get_formatted_text() -> StyleAndTextTuples:
+            buff = get_app().current_buffer
+
+            if buff.validation_error:
+                row, column = buff.document.translate_index_to_position(
+                    buff.validation_error.cursor_position
+                )
+
+                if show_position:
+                    text = "{} (line={} column={})".format(
+                        buff.validation_error.message,
+                        row + 1,
+                        column + 1,
+                    )
+                else:
+                    text = buff.validation_error.message
+
+                return [("class:validation-toolbar", text)]
+            else:
+                return []
+
+        self.control = FormattedTextControl(get_formatted_text)
+
+        self.container = ConditionalContainer(
+            content=Window(self.control, height=1), filter=has_validation_error
+        )
+
+    def __pt_container__(self) -> Container:
+        return self.container