Merge branch 'main' of github.com:Textualize/textual into datatable-cell-keys

.pre-commit-config.yaml

@@ -1,15 +1,22 @@
 # See https://pre-commit.com for more information
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
--   repo: https://github.com/pre-commit/pre-commit-hooks
+  - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.3.0
     hooks:
-    -   id: trailing-whitespace
+      - id: trailing-whitespace
-    -   id: end-of-file-fixer
+      - id: end-of-file-fixer
-    -   id: check-yaml
+      - id: check-yaml
-        args: ['--unsafe']
+        args: [ '--unsafe' ]
--   repo: https://github.com/psf/black
+  - repo: https://github.com/pycqa/isort
-    rev: 22.10.0
+    rev: 5.12.0
     hooks:
-    -   id: black
+      - id: isort
+        name: isort (python)
+        language_version: '3.11'
+        args: ["--profile", "black", "--filter-files"]
+  - repo: https://github.com/psf/black
+    rev: 23.1.0
+    hooks:
+      - id: black
 exclude: ^tests/snapshot_tests

CHANGELOG.md

@@ -19,11 +19,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added Shift+scroll wheel and ctrl+scroll wheel to scroll horizontally
 - Added `Tree.action_toggle_node` to toggle a node without selecting, and bound it to <kbd>Space</kbd> https://github.com/Textualize/textual/issues/1433
 - Added `Tree.reset` to fully reset a `Tree` https://github.com/Textualize/textual/issues/1437
+- Added DOMNode.watch and DOMNode.is_attached methods  https://github.com/Textualize/textual/pull/1750
 
 ### Changed
 
 - Breaking change: `TreeNode` can no longer be imported from `textual.widgets`; it is now available via `from textual.widgets.tree import TreeNode`. https://github.com/Textualize/textual/pull/1637
 - `Tree` now shows a (subdued) cursor for a highlighted node when focus has moved elsewhere https://github.com/Textualize/textual/issues/1471
+- Breaking change: renamed `Checkbox` to `Switch`.
 
 ### Fixed
 
@@ -42,6 +44,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Removed
 
 - Methods `MessagePump.emit` and `MessagePump.emit_no_wait` https://github.com/Textualize/textual/pull/1738
+- Removed `reactive.watch` in favor of DOMNode.watch.
 
 ## [0.10.1] - 2023-01-20
 

docs/api/checkbox.md

@@ -1 +0,0 @@
-::: textual.widgets.Checkbox

docs/api/switch.md

@@ -0,0 +1 @@
+::: textual.widgets.Switch

docs/examples/widgets/switch.css

@@ -7,7 +7,7 @@ Screen {
     width: auto;
 }
 
-Checkbox {
+Switch {
     height: auto;
     width: auto;
 }
@@ -22,7 +22,7 @@ Checkbox {
     background: darkslategrey;
 }
 
-#custom-design > .checkbox--switch {
+#custom-design > .switch--switch {
     color: dodgerblue;
     background: darkslateblue;
 }

docs/examples/widgets/switch.py

@@ -1,35 +1,35 @@
 from textual.app import App, ComposeResult
 from textual.containers import Horizontal
-from textual.widgets import Checkbox, Static
+from textual.widgets import Switch, Static
 
 
-class CheckboxApp(App):
+class SwitchApp(App):
     def compose(self) -> ComposeResult:
-        yield Static("[b]Example checkboxes\n", classes="label")
+        yield Static("[b]Example switches\n", classes="label")
         yield Horizontal(
             Static("off:     ", classes="label"),
-            Checkbox(animate=False),
+            Switch(animate=False),
             classes="container",
         )
         yield Horizontal(
             Static("on:      ", classes="label"),
-            Checkbox(value=True),
+            Switch(value=True),
             classes="container",
         )
 
-        focused_checkbox = Checkbox()
+        focused_switch = Switch()
-        focused_checkbox.focus()
+        focused_switch.focus()
         yield Horizontal(
-            Static("focused: ", classes="label"), focused_checkbox, classes="container"
+            Static("focused: ", classes="label"), focused_switch, classes="container"
         )
 
         yield Horizontal(
             Static("custom:  ", classes="label"),
-            Checkbox(id="custom-design"),
+            Switch(id="custom-design"),
             classes="container",
         )
 
 
-app = CheckboxApp(css_path="checkbox.css")
+app = SwitchApp(css_path="switch.css")
 if __name__ == "__main__":
     app.run()

docs/roadmap.md

@@ -40,7 +40,7 @@ Widgets are key to making user-friendly interfaces. The builtin widgets should c
 - [x] Buttons
     * [x] Error / warning variants
 - [ ] Color picker
-- [x] Checkbox
+- [ ] Checkbox
 - [ ] Content switcher
 - [x] DataTable
     * [x] Cell select
@@ -70,6 +70,7 @@ Widgets are key to making user-friendly interfaces. The builtin widgets should c
     * [ ] Style variants (solid, thin etc)
 - [ ] Radio boxes
 - [ ] Spark-lines
+- [X] Switch
 - [ ] Tabs
 - [ ] TextArea (multi-line input)
     * [ ] Basic controls

docs/widgets/checkbox.md

@@ -1,63 +0,0 @@
-# Checkbox
-
-A simple checkbox widget which stores a boolean value.
-
-- [x] Focusable
-- [ ] Container
-
-## Example
-
-The example below shows checkboxes in various states.
-
-=== "Output"
-
-    ```{.textual path="docs/examples/widgets/checkbox.py"}
-    ```
-
-=== "checkbox.py"
-
-    ```python
-    --8<-- "docs/examples/widgets/checkbox.py"
-    ```
-
-=== "checkbox.css"
-
-    ```sass
-    --8<-- "docs/examples/widgets/checkbox.css"
-    ```
-
-## Reactive Attributes
-
-| Name    | Type   | Default | Description                        |
-| ------- | ------ | ------- | ---------------------------------- |
-| `value` | `bool` | `False` | The default value of the checkbox. |
-
-## Bindings
-
-The checkbox widget defines directly the following bindings:
-
-::: textual.widgets.Checkbox.BINDINGS
-    options:
-      show_root_heading: false
-      show_root_toc_entry: false
-
-## Component Classes
-
-The checkbox widget provides the following component classes:
-
-::: textual.widgets.Checkbox.COMPONENT_CLASSES
-    options:
-      show_root_heading: false
-      show_root_toc_entry: false
-
-## Messages
-
-### ::: textual.widgets.Checkbox.Changed
-
-## Additional Notes
-
-- To remove the spacing around a checkbox, set `border: none;` and `padding: 0;`.
-
-## See Also
-
-- [Checkbox](../api/checkbox.md) code reference

docs/widgets/switch.md

@@ -0,0 +1,63 @@
+# Switch
+
+A simple switch widget which stores a boolean value.
+
+- [x] Focusable
+- [ ] Container
+
+## Example
+
+The example below shows switches in various states.
+
+=== "Output"
+
+    ```{.textual path="docs/examples/widgets/switch.py"}
+    ```
+
+=== "switch.py"
+
+    ```python
+    --8<-- "docs/examples/widgets/switch.py"
+    ```
+
+=== "switch.css"
+
+    ```sass
+    --8<-- "docs/examples/widgets/switch.css"
+    ```
+
+## Reactive Attributes
+
+| Name    | Type   | Default | Description                      |
+|---------|--------|---------|----------------------------------|
+| `value` | `bool` | `False` | The default value of the switch. |
+
+## Bindings
+
+The switch widget defines directly the following bindings:
+
+::: textual.widgets.Switch.BINDINGS
+    options:
+      show_root_heading: false
+      show_root_toc_entry: false
+
+## Component Classes
+
+The switch widget provides the following component classes:
+
+::: textual.widgets.Switch.COMPONENT_CLASSES
+    options:
+      show_root_heading: false
+      show_root_toc_entry: false
+
+## Messages
+
+### ::: textual.widgets.Switch.Changed
+
+## Additional Notes
+
+- To remove the spacing around a `Switch`, set `border: none;` and `padding: 0;`.
+
+## See Also
+
+- [Switch](../api/switch.md) code reference

mkdocs.yml

@@ -126,7 +126,6 @@ nav:
       - "styles/width.md"
     - Widgets:
       - "widgets/button.md"
-      - "widgets/checkbox.md"
       - "widgets/data_table.md"
       - "widgets/directory_tree.md"
       - "widgets/footer.md"
@@ -138,6 +137,7 @@ nav:
       - "widgets/list_view.md"
       - "widgets/placeholder.md"
       - "widgets/static.md"
+      - "widgets/switch.md"
       - "widgets/text_log.md"
       - "widgets/tree.md"
   - API:
@@ -145,7 +145,6 @@ nav:
     - "api/app.md"
     - "api/binding.md"
     - "api/button.md"
-    - "api/checkbox.md"
     - "api/color.md"
     - "api/containers.md"
     - "api/coordinate.md"
@@ -170,6 +169,7 @@ nav:
     - "api/scroll_view.md"
     - "api/static.md"
     - "api/strip.md"
+    - "api/switch.md"
     - "api/text_log.md"
     - "api/timer.md"
     - "api/tree.md"

src/textual/__init__.py

@@ -1,15 +1,14 @@
 from __future__ import annotations
 
 import inspect
+from typing import TYPE_CHECKING, Callable
 
 import rich.repr
 from rich.console import RenderableType
-from typing import Callable, TYPE_CHECKING
 
 from ._context import active_app
 from ._log import LogGroup, LogVerbosity
 
-
 if TYPE_CHECKING:
     from typing_extensions import TypeAlias
 

src/textual/__main__.py

@@ -1,6 +1,5 @@
 from .demo import DemoApp
 
-
 if __name__ == "__main__":
     app = DemoApp()
     app.run()

src/textual/_arrange.py

@@ -3,11 +3,11 @@ from __future__ import annotations
 from collections import defaultdict
 from fractions import Fraction
 from operator import attrgetter
-from typing import Sequence, TYPE_CHECKING
+from typing import TYPE_CHECKING, Sequence
 
-from .geometry import Region, Size, Spacing
 from ._layout import DockArrangeResult, WidgetPlacement
 from ._partition import partition
+from .geometry import Region, Size, Spacing
 
 if TYPE_CHECKING:
     from .widget import Widget

src/textual/_asyncio.py

@@ -5,7 +5,6 @@ Compatibility layer for asyncio.
 
 from __future__ import annotations
 
-
 import sys
 
 __all__ = ["create_task"]

src/textual/_border.py

@@ -1,8 +1,7 @@
 from __future__ import annotations
 
 from functools import lru_cache
-from typing import cast, Tuple, Union
+from typing import TYPE_CHECKING, Tuple, Union, cast
-from typing import TYPE_CHECKING
 
 from rich.segment import Segment
 from rich.style import Style

src/textual/_callback.py

@@ -2,8 +2,8 @@ from __future__ import annotations
 
 import asyncio
 from functools import lru_cache
-from inspect import signature, isawaitable
+from inspect import isawaitable, signature
-from typing import Any, Callable, TYPE_CHECKING
+from typing import TYPE_CHECKING, Any, Callable
 
 from . import active_app
 

src/textual/_clock.py

@@ -2,7 +2,6 @@ import asyncio
 
 from ._time import time
 
-
 """
 A module that serves as the single source of truth for everything time-related in a Textual app.
 Having this logic centralised makes it easier to simulate time in integration tests,

src/textual/_compositor.py

@@ -25,14 +25,14 @@ from rich.style import Style
 from . import errors
 from ._cells import cell_len
 from ._loop import loop_last
-from .strip import Strip
 from .geometry import NULL_OFFSET, Offset, Region, Size
-
+from .strip import Strip
 
 if TYPE_CHECKING:
-    from .widget import Widget
     from typing_extensions import TypeAlias
 
+    from .widget import Widget
+
 
 class ReflowResult(NamedTuple):
     """The result of a reflow operation. Describes the chances to widgets."""

src/textual/_context.py

@@ -1,6 +1,5 @@
-from typing import TYPE_CHECKING
-
 from contextvars import ContextVar
+from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from .app import App

src/textual/_doc.py

@@ -2,14 +2,13 @@ from __future__ import annotations
 
 import hashlib
 import os
-from pathlib import Path
 import shlex
+from pathlib import Path
 from typing import Iterable
 
+from textual._import_app import import_app
 from textual.app import App
 from textual.pilot import Pilot
-from textual._import_app import import_app
-
 
 SCREENSHOT_CACHE = ".screenshot_cache"
 

src/textual/_easing.py

@@ -3,7 +3,7 @@ Define a series of easing functions for more natural-looking animations.
 Taken from https://easings.net/ and translated from JavaScript.
 """
 
-from math import pi, cos, sin, sqrt
+from math import cos, pi, sin, sqrt
 
 
 def _in_out_expo(x: float) -> float:

src/textual/_immutable_sequence_view.py

@@ -1,8 +1,9 @@
 """Provides an immutable sequence view class."""
 
 from __future__ import annotations
+
 from sys import maxsize
-from typing import Generic, TypeVar, Iterator, overload, Sequence
+from typing import Generic, Iterator, Sequence, TypeVar, overload
 
 T = TypeVar("T")
 

src/textual/_import_app.py

@@ -1,12 +1,11 @@
 from __future__ import annotations
 
 import os
-import sys
 import runpy
 import shlex
+import sys
 from pathlib import Path
-from typing import cast, TYPE_CHECKING
+from typing import TYPE_CHECKING, cast
-
 
 if TYPE_CHECKING:
     from textual.app import App
@@ -46,10 +45,10 @@ def import_app(import_name: str) -> App:
         A Textual application
     """
 
-    import inspect
     import importlib
+    import inspect
 
-    from textual.app import App, WINDOWS
+    from textual.app import WINDOWS, App
 
     import_name, *argv = shlex.split(import_name, posix=not WINDOWS)
     drive, import_name = os.path.splitdrive(import_name)

src/textual/_layout.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from typing import ClassVar, NamedTuple, TYPE_CHECKING
+from typing import TYPE_CHECKING, ClassVar, NamedTuple
 
 from .geometry import Region, Size, Spacing
 
 if TYPE_CHECKING:
     from typing_extensions import TypeAlias
+
     from .widget import Widget
 
 ArrangeResult: TypeAlias = "tuple[list[WidgetPlacement], set[Widget]]"

src/textual/_node_list.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
-import sys
 
+import sys
 from typing import TYPE_CHECKING, Any, Iterator, Sequence, overload
 
 import rich.repr

src/textual/_parser.py

@@ -1,16 +1,8 @@
 from __future__ import annotations
 
-from collections import deque
 import io
-from typing import (
+from collections import deque
-    Callable,
+from typing import Callable, Deque, Generator, Generic, Iterable, TypeVar, Union
-    Deque,
-    Generator,
-    TypeVar,
-    Generic,
-    Union,
-    Iterable,
-)
 
 
 class ParseError(Exception):

src/textual/_partition.py

@@ -2,7 +2,6 @@ from __future__ import annotations
 
 from typing import Callable, Iterable, TypeVar
 
-
 T = TypeVar("T")
 
 

src/textual/_profile.py

@@ -4,8 +4,8 @@ Timer context manager, only used in debug.
 """
 
 import contextlib
-from typing import Generator
 from time import perf_counter
+from typing import Generator
 
 from . import log
 

src/textual/_resolve.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from fractions import Fraction
 from itertools import accumulate
-from typing import Sequence, cast, TYPE_CHECKING
+from typing import TYPE_CHECKING, Sequence, cast
 
 from typing_extensions import Literal
 

src/textual/_sleep.py

@@ -1,9 +1,8 @@
 from __future__ import annotations
 
-
+from asyncio import Future, get_running_loop
-from time import sleep, perf_counter
+from threading import Event, Thread
-from asyncio import get_running_loop, Future
+from time import perf_counter, sleep
-from threading import Thread, Event
 
 
 class Sleeper(Thread):

src/textual/_wait.py

@@ -1,5 +1,5 @@
 from asyncio import sleep
-from time import process_time, monotonic
+from time import monotonic, process_time
 
 SLEEP_GRANULARITY: float = 1 / 50
 SLEEP_IDLE: float = SLEEP_GRANULARITY / 2.0

src/textual/_win_sleep.py

@@ -7,7 +7,6 @@ This should only be imported on Windows.
 
 from time import sleep as time_sleep
 
-
 __all__ = ["sleep"]
 
 

src/textual/_xterm_parser.py

@@ -1,17 +1,15 @@
 from __future__ import annotations
 
-import unicodedata
 import re
+import unicodedata
 from typing import Any, Callable, Generator, Iterable
 
-from . import events
+from . import events, messages
-from . import messages
 from ._ansi_sequences import ANSI_SEQUENCES_KEYS
 from ._parser import Awaitable, Parser, TokenCallback
 from ._types import MessageTarget
 from .keys import KEY_NAME_REPLACEMENTS
 
-
 # When trying to determine whether the current sequence is a supported/valid
 # escape sequence, at which length should we give up and consider our search
 # to be unsuccessful?

src/textual/app.py

@@ -48,9 +48,7 @@ from ._asyncio import create_task
 from ._callback import invoke
 from ._context import active_app
 from ._event_broker import NoHandler, extract_handler_actions
-from .filter import LineFilter, Monochrome
 from ._path import _make_path_object_relative
-
 from ._wait import wait_for_idle
 from .actions import SkipAction
 from .await_remove import AwaitRemove
@@ -63,6 +61,7 @@ from .driver import Driver
 from .drivers.headless_driver import HeadlessDriver
 from .features import FeatureFlag, parse_features
 from .file_monitor import FileMonitor
+from .filter import LineFilter, Monochrome
 from .geometry import Offset, Region, Size
 from .keys import REPLACED_KEYS, _get_key_display
 from .messages import CallbackType

src/textual/case.py

@@ -1,5 +1,4 @@
 import re
-
 from typing import Match, Pattern
 
 

src/textual/cli/cli.py

@@ -10,8 +10,8 @@ except ImportError:
 
 from importlib_metadata import version
 
+from textual._import_app import AppFail, import_app
 from textual.pilot import Pilot
-from textual._import_app import import_app, AppFail
 
 
 @click.group()
@@ -26,6 +26,7 @@ def run():
 def console(verbose: bool, exclude: list[str]) -> None:
     """Launch the textual console."""
     from rich.console import Console
+
     from textual.devtools.server import _run_devtools
 
     console = Console()

src/textual/cli/previews/borders.py

@@ -1,8 +1,7 @@
 from textual.app import App, ComposeResult
 from textual.constants import BORDERS
-from textual.widgets import Button, Label
 from textual.containers import Vertical
-
+from textual.widgets import Button, Label
 
 TEXT = """I must not fear.
 Fear is the mind-killer.

src/textual/cli/previews/colors.py

@@ -2,7 +2,7 @@ from textual.app import App, ComposeResult
 from textual.containers import Horizontal, Vertical
 from textual.design import ColorSystem
 from textual.widget import Widget
-from textual.widgets import Button, Footer, Static, Label
+from textual.widgets import Button, Footer, Label, Static
 
 
 class ColorButtons(Vertical):

src/textual/cli/previews/easing.py

@@ -1,14 +1,15 @@
 from __future__ import annotations
 
 from rich.console import RenderableType
+
 from textual._easing import EASING
 from textual.app import App, ComposeResult
 from textual.cli.previews.borders import TEXT
 from textual.containers import Container, Horizontal, Vertical
-from textual.reactive import Reactive
+from textual.reactive import reactive, var
 from textual.scrollbar import ScrollBarRender
 from textual.widget import Widget
-from textual.widgets import Button, Footer, Label, Input
+from textual.widgets import Button, Footer, Input, Label
 
 VIRTUAL_SIZE = 100
 WINDOW_SIZE = 10
@@ -23,8 +24,8 @@ class EasingButtons(Widget):
 
 
 class Bar(Widget):
-    position = Reactive.init(START_POSITION)
+    position = reactive(START_POSITION)
-    animation_running = Reactive(False)
+    animation_running = reactive(False)
 
     DEFAULT_CSS = """
 
@@ -53,8 +54,8 @@ class Bar(Widget):
 
 
 class EasingApp(App):
-    position = Reactive.init(START_POSITION)
+    position = reactive(START_POSITION)
-    duration = Reactive.var(1.0)
+    duration = var(1.0)
 
     def on_load(self):
         self.bind(

src/textual/cli/previews/keys.py

@@ -1,16 +1,14 @@
 from __future__ import annotations
 
 from rich.panel import Panel
-
 from rich.text import Text
 
-from textual.app import App, ComposeResult
-from textual.reactive import var, Reactive
 from textual import events
+from textual.app import App, ComposeResult
 from textual.containers import Horizontal
+from textual.reactive import Reactive, var
 from textual.widgets import Button, Header, TextLog
 
-
 INSTRUCTIONS = """\
 [u]Press some keys![/]
 

src/textual/cli/tools/diagnose.py

@@ -1,11 +1,13 @@
 """Textual CLI command code to print diagnostic information."""
 
 from __future__ import annotations
+
 import os
-import sys
 import platform
-from typing import Any
+import sys
 from functools import singledispatch
+from typing import Any
+
 from importlib_metadata import version
 from rich.console import Console, ConsoleDimensions
 

src/textual/css/_help_text.py

@@ -5,20 +5,20 @@ from typing import Iterable, Sequence
 
 from typing_extensions import Literal
 
+from textual.css._error_tools import friendly_list
+from textual.css.scalar import SYMBOL_UNIT
+
 from ..color import ColorParseError
-from ._help_renderables import Example, Bullet, HelpText
+from ._help_renderables import Bullet, Example, HelpText
 from .constants import (
-    VALID_BORDER,
-    VALID_LAYOUT,
     VALID_ALIGN_HORIZONTAL,
     VALID_ALIGN_VERTICAL,
+    VALID_BORDER,
+    VALID_LAYOUT,
     VALID_STYLE_FLAGS,
     VALID_TEXT_ALIGN,
 )
 
-from textual.css._error_tools import friendly_list
-from textual.css.scalar import SYMBOL_UNIT
-
 StylingContext = Literal["inline", "css"]
 """The type of styling the user was using when the error was encountered.
 Used to give help text specific to the context i.e. we give CSS help if the

src/textual/css/_style_properties.py

@@ -10,14 +10,7 @@ when setting and getting.
 from __future__ import annotations
 
 from operator import attrgetter
-from typing import (
+from typing import TYPE_CHECKING, Generic, Iterable, NamedTuple, TypeVar, cast
-    TYPE_CHECKING,
-    Generic,
-    Iterable,
-    NamedTuple,
-    TypeVar,
-    cast,
-)
 
 import rich.errors
 import rich.repr
@@ -611,11 +604,8 @@ class LayoutProperty:
                 or a ``Layout`` object.
         """
 
-        from ..layouts.factory import (
+        from ..layouts.factory import Layout  # Prevents circular import
-            Layout,  # Prevents circular import
+        from ..layouts.factory import MissingLayout, get_layout
-            MissingLayout,
-            get_layout,
-        )
 
         _rich_traceback_omit = True
         if layout is None:

src/textual/css/constants.py

@@ -1,4 +1,5 @@
 from __future__ import annotations
+
 import typing
 
 from ..geometry import Spacing

src/textual/css/errors.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from rich.console import ConsoleOptions, Console, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult
 from rich.traceback import Traceback
 
 from ._help_renderables import HelpText

src/textual/css/match.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
-from typing import Iterable, TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable
-from .model import CombinatorType, Selector, SelectorSet
 
+from .model import CombinatorType, Selector, SelectorSet
 
 if TYPE_CHECKING:
     from ..dom import DOMNode

src/textual/css/model.py

@@ -1,11 +1,10 @@
 from __future__ import annotations
 
-
-import rich.repr
-
 from dataclasses import dataclass, field
 from enum import Enum
-from typing import Iterable, TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable
+
+import rich.repr
 
 from .styles import Styles
 from .tokenize import Token

src/textual/css/parse.py

@@ -2,23 +2,23 @@ from __future__ import annotations
 
 from functools import lru_cache
 from pathlib import PurePath
-from typing import Iterator, Iterable, NoReturn
+from typing import Iterable, Iterator, NoReturn
 
+from ..suggestions import get_suggestion
+from ._styles_builder import DeclarationError, StylesBuilder
 from .errors import UnresolvedVariableError
-from .types import Specificity3
-from ._styles_builder import StylesBuilder, DeclarationError
 from .model import (
+    CombinatorType,
     Declaration,
     RuleSet,
     Selector,
-    CombinatorType,
     SelectorSet,
     SelectorType,
 )
 from .styles import Styles
-from ..suggestions import get_suggestion
+from .tokenize import Token, tokenize, tokenize_declarations, tokenize_values
-from .tokenize import tokenize, tokenize_declarations, Token, tokenize_values
 from .tokenizer import EOFError, ReferencedBy
+from .types import Specificity3
 
 SELECTOR_MAP: dict[str, tuple[SelectorType, Specificity3]] = {
     "selector": (SelectorType.TYPE, (0, 0, 1)),

src/textual/css/scalar.py

@@ -1,9 +1,9 @@
 from __future__ import annotations
 
+import re
 from enum import Enum, unique
 from fractions import Fraction
 from functools import lru_cache
-import re
 from typing import Iterable, NamedTuple
 
 import rich.repr

src/textual/css/scalar_animation.py

@@ -2,15 +2,12 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
-from .scalar import ScalarOffset, Scalar
+from .._animator import Animation, EasingFunction
-from .._animator import Animation
-from .._animator import EasingFunction
 from .._types import CallbackType
-
+from .scalar import Scalar, ScalarOffset
 
 if TYPE_CHECKING:
     from ..dom import DOMNode
-
     from .styles import StylesBase
 
 

src/textual/css/styles.py

@@ -4,8 +4,7 @@ from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
 from functools import lru_cache
 from operator import attrgetter
-from typing import Iterable, cast
+from typing import TYPE_CHECKING, Any, Iterable, NamedTuple, cast
-from typing import TYPE_CHECKING, Any, NamedTuple
 
 import rich.repr
 from rich.style import Style

src/textual/css/tokenize.py

@@ -4,7 +4,7 @@ import re
 from pathlib import PurePath
 from typing import Iterable
 
-from textual.css.tokenizer import Expect, Tokenizer, Token
+from textual.css.tokenizer import Expect, Token, Tokenizer
 
 PERCENT = r"-?\d+\.?\d*%"
 DECIMAL = r"-?\d+\.?\d*"

src/textual/css/tokenizer.py

@@ -4,11 +4,11 @@ import re
 from pathlib import PurePath
 from typing import NamedTuple
 
+import rich.repr
 from rich.console import Group, RenderableType
 from rich.highlighter import ReprHighlighter
 from rich.padding import Padding
 from rich.panel import Panel
-import rich.repr
 from rich.syntax import Syntax
 from rich.text import Text
 

src/textual/css/types.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from typing import Tuple
+
 from typing_extensions import Literal
 
 from ..color import Color

src/textual/demo.css

@@ -119,7 +119,7 @@ DarkSwitch .label {
     color: $text-muted;
 }
 
-DarkSwitch Checkbox {
+DarkSwitch Switch {
     background: $boost;
     dock: left;
 }

src/textual/demo.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
-from importlib_metadata import version
 from pathlib import Path
 
+from importlib_metadata import version
 from rich import box
 from rich.console import RenderableType
 from rich.json import JSON
@@ -15,15 +15,15 @@ from rich.text import Text
 from textual.app import App, ComposeResult
 from textual.binding import Binding
 from textual.containers import Container, Horizontal
-from textual.reactive import reactive, watch
+from textual.reactive import reactive
 from textual.widgets import (
     Button,
-    Checkbox,
     DataTable,
     Footer,
     Header,
     Input,
     Static,
+    Switch,
     TextLog,
 )
 
@@ -138,7 +138,7 @@ Build your own or use the builtin widgets.
 
 - **Input** Text / Password input.
 - **Button** Clickable button with a number of styles.
-- **Checkbox** A checkbox to toggle between states.
+- **Switch** A switch to toggle between states.
 - **DataTable** A spreadsheet-like widget for navigating data. Cells may contain text or Rich renderables.
 - **Tree** An generic tree with expandable nodes.
 - **DirectoryTree** A tree of file and folders.
@@ -199,16 +199,16 @@ class Title(Static):
 
 class DarkSwitch(Horizontal):
     def compose(self) -> ComposeResult:
-        yield Checkbox(value=self.app.dark)
+        yield Switch(value=self.app.dark)
         yield Static("Dark mode toggle", classes="label")
 
     def on_mount(self) -> None:
-        watch(self.app, "dark", self.on_dark_change, init=False)
+        self.watch(self.app, "dark", self.on_dark_change, init=False)
 
     def on_dark_change(self, dark: bool) -> None:
-        self.query_one(Checkbox).value = self.app.dark
+        self.query_one(Switch).value = self.app.dark
 
-    def on_checkbox_changed(self, event: Checkbox.Changed) -> None:
+    def on_switch_changed(self, event: Switch.Changed) -> None:
         self.app.dark = event.value
 
 

src/textual/design.py

@@ -7,8 +7,7 @@ from rich.padding import Padding
 from rich.table import Table
 from rich.text import Text
 
-from .color import Color, WHITE
+from .color import WHITE, Color
-
 
 NUMBER_OF_SHADES = 3
 

src/textual/devtools/client.py

@@ -9,21 +9,14 @@ from io import StringIO
 from time import time
 from typing import Any, NamedTuple, Type
 
+import aiohttp
+import msgpack
+from aiohttp import ClientConnectorError, ClientResponseError, ClientWebSocketResponse
 from rich.console import Console
 from rich.segment import Segment
 
 from .._log import LogGroup, LogVerbosity
 
-
-import aiohttp
-import msgpack
-from aiohttp import (
-    ClientConnectorError,
-    ClientResponseError,
-    ClientWebSocketResponse,
-)
-
-
 DEVTOOLS_PORT = 8081
 WEBSOCKET_CONNECT_TIMEOUT = 3
 LOG_QUEUE_MAXSIZE = 512

src/textual/devtools/redirect_output.py

@@ -1,10 +1,10 @@
 from __future__ import annotations
 
 import inspect
-
 from typing import TYPE_CHECKING, cast
-from .client import DevtoolsLog
+
 from .._log import LogGroup, LogVerbosity
+from .client import DevtoolsLog
 
 if TYPE_CHECKING:
     from .client import DevtoolsClient

src/textual/devtools/server.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+
 from aiohttp.web import run_app
 from aiohttp.web_app import Application
 from aiohttp.web_request import Request

src/textual/devtools/service.py

@@ -7,19 +7,19 @@ import pickle
 from json import JSONDecodeError
 from typing import Any, cast
 
+import msgpack
 from aiohttp import WSMessage, WSMsgType
 from aiohttp.abc import Request
 from aiohttp.web_ws import WebSocketResponse
 from rich.console import Console
 from rich.markup import escape
-import msgpack
 
 from textual._log import LogGroup
 from textual._time import time
 from textual.devtools.renderables import (
+    DevConsoleHeader,
     DevConsoleLog,
     DevConsoleNotice,
-    DevConsoleHeader,
 )
 
 QUEUEABLE_TYPES = {"client_log", "client_spillover"}

src/textual/dom.py

@@ -22,6 +22,7 @@ from rich.tree import Tree
 
 from ._context import NoActiveAppError
 from ._node_list import NodeList
+from ._types import CallbackType
 from .binding import Bindings, BindingType
 from .color import BLACK, WHITE, Color
 from .css._error_tools import friendly_list
@@ -31,7 +32,7 @@ from .css.parse import parse_declarations
 from .css.styles import RenderStyles, Styles
 from .css.tokenize import IDENTIFIER
 from .message_pump import MessagePump
-from .reactive import Reactive
+from .reactive import Reactive, _watch
 from .timer import Timer
 from .walk import walk_breadth_first, walk_depth_first
 
@@ -210,6 +211,10 @@ class DOMNode(MessagePump):
         styles = self._component_styles[name]
         return styles
 
+    def _post_mount(self):
+        """Called after the object has been mounted."""
+        Reactive._initialize_object(self)
+
     @property
     def _node_bases(self) -> Iterator[Type[DOMNode]]:
         """Iterator[Type[DOMNode]]: The DOMNode bases classes (including self.__class__)"""
@@ -643,6 +648,23 @@ class DOMNode(MessagePump):
         """
         return [child for child in self.children if child.display]
 
+    def watch(
+        self,
+        obj: DOMNode,
+        attribute_name: str,
+        callback: CallbackType,
+        init: bool = True,
+    ) -> None:
+        """Watches for modifications to reactive attributes on another object.
+
+        Args:
+            obj: Object containing attribute to watch.
+            attribute_name: Attribute to watch.
+            callback: A callback to run when attribute changes.
+            init: Check watchers on first call.
+        """
+        _watch(self, obj, attribute_name, callback, init=init)
+
     def get_pseudo_classes(self) -> Iterable[str]:
         """Get any pseudo classes applicable to this Node, e.g. hover, focus.
 

src/textual/drivers/headless_driver.py

@@ -1,9 +1,10 @@
 from __future__ import annotations
 
 import asyncio
+
+from .. import events
 from ..driver import Driver
 from ..geometry import Size
-from .. import events
 
 
 class HeadlessDriver(Driver):

src/textual/drivers/linux_driver.py

@@ -2,27 +2,26 @@ from __future__ import annotations
 
 import asyncio
 import os
-from codecs import getincrementaldecoder
 import selectors
 import signal
 import sys
 import termios
 import tty
-from typing import Any, TYPE_CHECKING
+from codecs import getincrementaldecoder
 from threading import Event, Thread
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from rich.console import Console
 
 import rich.repr
 
-from .. import log
+from .. import events, log
-from ..driver import Driver
+from .._profile import timer
-from ..geometry import Size
 from .._types import MessageTarget
 from .._xterm_parser import XTermParser
-from .._profile import timer
+from ..driver import Driver
-from .. import events
+from ..geometry import Size
 
 
 @rich.repr.auto

src/textual/geometry.py

@@ -9,6 +9,7 @@ from __future__ import annotations
 from functools import lru_cache
 from operator import attrgetter, itemgetter
 from typing import (
+    TYPE_CHECKING,
     Any,
     Collection,
     NamedTuple,
@@ -16,7 +17,6 @@ from typing import (
     TypeVar,
     Union,
     cast,
-    TYPE_CHECKING,
 )
 
 if TYPE_CHECKING:

src/textual/layouts/factory.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
 from .._layout import Layout
-from .horizontal import HorizontalLayout
 from .grid import GridLayout
+from .horizontal import HorizontalLayout
 from .vertical import VerticalLayout
 
 LAYOUT_MAP: dict[str, type[Layout]] = {

src/textual/layouts/horizontal.py

@@ -2,9 +2,9 @@ from __future__ import annotations
 
 from fractions import Fraction
 
-from .._resolve import resolve_box_models
-from ..geometry import Size, Region
 from .._layout import ArrangeResult, Layout, WidgetPlacement
+from .._resolve import resolve_box_models
+from ..geometry import Region, Size
 from ..widget import Widget
 
 

src/textual/layouts/vertical.py

@@ -3,9 +3,9 @@ from __future__ import annotations
 from fractions import Fraction
 from typing import TYPE_CHECKING
 
+from .._layout import ArrangeResult, Layout, WidgetPlacement
 from .._resolve import resolve_box_models
 from ..geometry import Region, Size
-from .._layout import ArrangeResult, Layout, WidgetPlacement
 
 if TYPE_CHECKING:
     from ..widget import Widget

src/textual/message.py

@@ -1,15 +1,16 @@
 from __future__ import annotations
 
-from typing import ClassVar, TYPE_CHECKING
+from typing import TYPE_CHECKING, ClassVar
 
 import rich.repr
 
 from . import _clock
-from .case import camel_to_snake
 from ._types import MessageTarget as MessageTarget
+from .case import camel_to_snake
 
 if TYPE_CHECKING:
     from .message_pump import MessagePump
+    from .widget import Widget
 
 
 @rich.repr.auto

src/textual/message_pump.py

@@ -123,6 +123,19 @@ class MessagePump(metaclass=MessagePumpMeta):
         """
         return self.app._logger
 
+    @property
+    def is_attached(self) -> bool:
+        """Is the node is attached to the app via the DOM."""
+        from .app import App
+
+        node = self
+
+        while not isinstance(node, App):
+            if node._parent is None:
+                return False
+            node = node._parent
+        return True
+
     def _attach(self, parent: MessagePump) -> None:
         """Set the parent, and therefore attach this node to the tree.
 
@@ -358,7 +371,10 @@ class MessagePump(metaclass=MessagePumpMeta):
         finally:
             # This is critical, mount may be waiting
             self._mounted_event.set()
-        Reactive._initialize_object(self)
+        self._post_mount()
+
+    def _post_mount(self):
+        """Called after the object has been mounted."""
 
     async def _process_messages_loop(self) -> None:
         """Process messages until the queue is closed."""

src/textual/messages.py

@@ -1,13 +1,13 @@
 from __future__ import annotations
+
 from typing import TYPE_CHECKING
 
 import rich.repr
 
-from .geometry import Region
 from ._types import CallbackType
+from .geometry import Region
 from .message import Message
 
-
 if TYPE_CHECKING:
     from .message_pump import MessagePump
     from .widget import Widget

src/textual/pilot.py

@@ -1,12 +1,12 @@
 from __future__ import annotations
 
-import rich.repr
-
 import asyncio
 from typing import Generic
 
-from .app import App, ReturnType
+import rich.repr
+
 from ._wait import wait_for_idle
+from .app import App, ReturnType
 
 
 @rich.repr.auto(angular=True)
@@ -53,6 +53,7 @@ class Pilot(Generic[ReturnType]):
     async def wait_for_scheduled_animations(self) -> None:
         """Wait for any current and scheduled animations to complete."""
         await self._app.animator.wait_until_complete()
+        await wait_for_idle(0)
 
     async def exit(self, result: ReturnType) -> None:
         """Exit the app with the given result.

src/textual/reactive.py

@@ -7,36 +7,26 @@ from typing import (
     Any,
     Awaitable,
     Callable,
+    ClassVar,
     Generic,
     Type,
     TypeVar,
-    Union,
 )
 
 import rich.repr
 
 from . import events
-from ._callback import count_parameters, invoke
+from ._callback import count_parameters
-from ._types import MessageTarget
+from ._types import CallbackType, MessageTarget
 
 if TYPE_CHECKING:
-    from .app import App
+    from .dom import DOMNode
-    from .widget import Widget
 
-    Reactable = Union[Widget, App]
+    Reactable = DOMNode
 
 ReactiveType = TypeVar("ReactiveType")
 
 
-class _NotSet:
-    pass
-
-
-_NOT_SET = _NotSet()
-
-T = TypeVar("T")
-
-
 @rich.repr.auto
 class Reactive(Generic[ReactiveType]):
     """Reactive descriptor.
@@ -50,7 +40,7 @@ class Reactive(Generic[ReactiveType]):
         compute: Run compute methods when attribute is changed. Defaults to True.
     """
 
-    _reactives: TypeVar[dict[str, object]] = {}
+    _reactives: ClassVar[dict[str, object]] = {}
 
     def __init__(
         self,
@@ -77,37 +67,6 @@ class Reactive(Generic[ReactiveType]):
         yield "always_update", self._always_update
         yield "compute", self._run_compute
 
-    @classmethod
-    def init(
-        cls,
-        default: ReactiveType | Callable[[], ReactiveType],
-        *,
-        layout: bool = False,
-        repaint: bool = True,
-        always_update: bool = False,
-        compute: bool = True,
-    ) -> Reactive:
-        """A reactive variable that calls watchers and compute on initialize (post mount).
-
-        Args:
-            default: A default value or callable that returns a default.
-            layout: Perform a layout on change. Defaults to False.
-            repaint: Perform a repaint on change. Defaults to True.
-            always_update: Call watchers even when the new value equals the old value. Defaults to False.
-            compute: Run compute methods when attribute is changed. Defaults to True.
-
-        Returns:
-            A Reactive instance which calls watchers or initialize.
-        """
-        return cls(
-            default,
-            layout=layout,
-            repaint=repaint,
-            init=True,
-            always_update=always_update,
-            compute=compute,
-        )
-
     @classmethod
     def var(
         cls,
@@ -254,7 +213,7 @@ class Reactive(Generic[ReactiveType]):
 
         def invoke_watcher(
             watch_function: Callable, old_value: object, value: object
-        ) -> bool:
+        ) -> None:
             """Invoke a watch function.
 
             Args:
@@ -262,8 +221,6 @@ class Reactive(Generic[ReactiveType]):
                 old_value: The old value of the attribute.
                 value: The new value of the attribute.
 
-            Returns:
-                True if the watcher was run, or False if it was posted.
             """
             _rich_traceback_omit = True
             param_count = count_parameters(watch_function)
@@ -280,17 +237,23 @@ class Reactive(Generic[ReactiveType]):
                         sender=obj, callback=partial(await_watcher, watch_result)
                     )
                 )
-                return False
-            else:
-                return True
 
         watch_function = getattr(obj, f"watch_{name}", None)
         if callable(watch_function):
             invoke_watcher(watch_function, old_value, value)
 
-        watchers: list[Callable] = getattr(obj, "__watchers", {}).get(name, [])
+        # Process "global" watchers
-        for watcher in watchers:
+        watchers: list[tuple[Reactable, Callable]]
-            invoke_watcher(watcher, old_value, value)
+        watchers = getattr(obj, "__watchers", {}).get(name, [])
+        # Remove any watchers for reactables that have since closed
+        if watchers:
+            watchers[:] = [
+                (reactable, callback)
+                for reactable, callback in watchers
+                if reactable.is_attached and not reactable._closing
+            ]
+            for _, callback in watchers:
+                invoke_watcher(callback, old_value, value)
 
     @classmethod
     def _compute(cls, obj: Reactable) -> None:
@@ -362,10 +325,12 @@ class var(Reactive[ReactiveType]):
         )
 
 
-def watch(
+def _watch(
+    node: DOMNode,
     obj: Reactable,
     attribute_name: str,
-    callback: Callable[[Any], object],
+    callback: CallbackType,
+    *,
     init: bool = True,
 ) -> None:
     """Watch a reactive variable on an object.
@@ -379,11 +344,11 @@ def watch(
 
     if not hasattr(obj, "__watchers"):
         setattr(obj, "__watchers", {})
-    watchers: dict[str, list[Callable]] = getattr(obj, "__watchers")
+    watchers: dict[str, list[tuple[Reactable, Callable]]] = getattr(obj, "__watchers")
     watcher_list = watchers.setdefault(attribute_name, [])
     if callback in watcher_list:
         return
-    watcher_list.append(callback)
+    watcher_list.append((node, callback))
     if init:
         current_value = getattr(obj, attribute_name, None)
         Reactive._check_watchers(obj, attribute_name, current_value)

src/textual/renderables/blank.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from rich.console import ConsoleOptions, Console, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult
 from rich.segment import Segment
 from rich.style import Style
 

src/textual/renderables/gradient.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
-from rich.console import ConsoleOptions, Console, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult
-
 from rich.segment import Segment
 from rich.style import Style
 

src/textual/renderables/sparkline.py

@@ -1,10 +1,10 @@
 from __future__ import annotations
 
 import statistics
-from typing import Generic, Sequence, Iterable, Callable, TypeVar
+from typing import Callable, Generic, Iterable, Sequence, TypeVar
 
 from rich.color import Color
-from rich.console import ConsoleOptions, Console, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult
 from rich.segment import Segment
 from rich.style import Style
 

src/textual/renderables/text_opacity.py

@@ -3,7 +3,7 @@ from typing import Iterable, Tuple, cast
 
 from rich.cells import cell_len
 from rich.color import Color
-from rich.console import ConsoleOptions, Console, RenderResult, RenderableType
+from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
 from rich.segment import Segment
 from rich.style import Style
 

src/textual/renderables/tint.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from typing import Iterable
 
-from rich.console import ConsoleOptions, Console, RenderResult, RenderableType
+from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
 from rich.segment import Segment
 from rich.style import Style
 

src/textual/renderables/underline_bar.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from rich.console import ConsoleOptions, Console, RenderResult
+from rich.console import Console, ConsoleOptions, RenderResult
 from rich.style import StyleType
 from rich.text import Text
 
@@ -99,6 +99,7 @@ class UnderlineBar:
 if __name__ == "__main__":
     import random
     from time import sleep
+
     from rich.color import ANSI_COLOR_NAMES
 
     console = Console()

src/textual/screen.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Iterable, Iterator, TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable, Iterator
 
 import rich.repr
 from rich.console import RenderableType
@@ -9,14 +9,14 @@ from rich.style import Style
 from . import errors, events, messages
 from ._callback import invoke
 from ._compositor import Compositor, MapGeometry
+from ._types import CallbackType
 from .css.match import match
 from .css.parse import parse_selectors
 from .dom import DOMNode
-from .timer import Timer
-from ._types import CallbackType
 from .geometry import Offset, Region, Size
 from .reactive import Reactive
 from .renderables.blank import Blank
+from .timer import Timer
 from .widget import Widget
 
 if TYPE_CHECKING:

src/textual/walk.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from collections import deque
-from typing import Iterable, Iterator, TypeVar, overload, TYPE_CHECKING
+from typing import TYPE_CHECKING, Iterable, Iterator, TypeVar, overload
 
 if TYPE_CHECKING:
     from textual.dom import DOMNode

src/textual/widget.py

@@ -35,9 +35,9 @@ from rich.text import Text
 from rich.traceback import Traceback
 
 from . import errors, events, messages
-from ._asyncio import create_task
 from ._animator import DEFAULT_EASING, Animatable, BoundAnimator, EasingFunction
 from ._arrange import DockArrangeResult, arrange
+from ._asyncio import create_task
 from ._context import active_app
 from ._easing import DEFAULT_SCROLL_EASING
 from ._layout import Layout

src/textual/widgets/__init__.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
-from importlib import import_module
+
 import typing
+from importlib import import_module
 
 from ..case import camel_to_snake
 
@@ -8,8 +9,8 @@ from ..case import camel_to_snake
 # but also to the `__init__.pyi` file in this same folder - otherwise text editors and type checkers won't
 # be able to "see" them.
 if typing.TYPE_CHECKING:
+    from ..widget import Widget
     from ._button import Button
-    from ._checkbox import Checkbox
     from ._data_table import DataTable
     from ._directory_tree import DirectoryTree
     from ._footer import Footer
@@ -21,15 +22,15 @@ if typing.TYPE_CHECKING:
     from ._placeholder import Placeholder
     from ._pretty import Pretty
     from ._static import Static
+    from ._switch import Switch
     from ._text_log import TextLog
     from ._tree import Tree
     from ._welcome import Welcome
-    from ..widget import Widget
 
 
 __all__ = [
     "Button",
-    "Checkbox",
+    "Switch",
     "DataTable",
     "DirectoryTree",
     "Footer",

src/textual/widgets/__init__.pyi

@@ -1,18 +1,17 @@
 # This stub file must re-export every classes exposed in the __init__.py's `__all__` list:
 from ._button import Button as Button
 from ._data_table import DataTable as DataTable
-from ._checkbox import Checkbox as Checkbox
 from ._directory_tree import DirectoryTree as DirectoryTree
 from ._footer import Footer as Footer
 from ._header import Header as Header
+from ._input import Input as Input
 from ._label import Label as Label
-from ._list_view import ListView as ListView
 from ._list_item import ListItem as ListItem
+from ._list_view import ListView as ListView
 from ._placeholder import Placeholder as Placeholder
 from ._pretty import Pretty as Pretty
 from ._static import Static as Static
-from ._input import Input as Input
+from ._switch import Switch as Switch
 from ._text_log import TextLog as TextLog
 from ._tree import Tree as Tree
-from ._tree_node import TreeNode as TreeNode
 from ._welcome import Welcome as Welcome

src/textual/widgets/_button.py

@@ -2,19 +2,18 @@ from __future__ import annotations
 
 from functools import partial
 from typing import cast
-from typing_extensions import Literal
 
 import rich.repr
 from rich.console import RenderableType
 from rich.text import Text, TextType
+from typing_extensions import Literal
 
 from .. import events
 from ..css._error_tools import friendly_list
 from ..message import Message
-from ..reactive import Reactive
+from ..reactive import reactive
 from ..widgets import Static
 
-
 ButtonVariant = Literal["default", "primary", "success", "warning", "error"]
 _VALID_BUTTON_VARIANTS = {"default", "primary", "success", "warning", "error"}
 
@@ -151,13 +150,13 @@ class Button(Static, can_focus=True):
     ACTIVE_EFFECT_DURATION = 0.3
     """When buttons are clicked they get the `-active` class for this duration (in seconds)"""
 
-    label: Reactive[RenderableType] = Reactive("")
+    label: reactive[RenderableType] = reactive("")
     """The text label that appears within the button."""
 
-    variant = Reactive.init("default")
+    variant = reactive("default")
     """The variant name for the button."""
 
-    disabled = Reactive(False)
+    disabled = reactive(False)
     """The disabled state of the button; `True` if disabled, `False` if not."""
 
     class Pressed(Message, bubble=True):

src/textual/widgets/_data_table.py

@@ -15,7 +15,7 @@ from rich.style import Style
 from rich.text import Text, TextType
 from typing_extensions import Literal, TypeAlias
 
-from .. import events, messages
+from .. import events
 from .._cache import LRUCache
 from .._segment_tools import line_crop
 from .._two_way_dict import TwoWayDict

src/textual/widgets/_directory_tree.py

@@ -7,9 +7,9 @@ from typing import ClassVar
 from rich.style import Style
 from rich.text import Text, TextType
 
-from ..message import Message
-from ._tree import Tree, TreeNode, TOGGLE_STYLE
 from .._types import MessageTarget
+from ..message import Message
+from ._tree import TOGGLE_STYLE, Tree, TreeNode
 
 
 @dataclass

src/textual/widgets/_footer.py

@@ -8,7 +8,7 @@ from rich.console import RenderableType
 from rich.text import Text
 
 from .. import events
-from ..reactive import Reactive, watch
+from ..reactive import Reactive
 from ..widget import Widget
 
 
@@ -66,7 +66,7 @@ class Footer(Widget):
         self.refresh()
 
     def on_mount(self) -> None:
-        watch(self.screen, "focused", self._focus_changed)
+        self.watch(self.screen, "focused", self._focus_changed)
 
     def _focus_changed(self, focused: Widget | None) -> None:
         self._key_text = None

src/textual/widgets/_header.py

@@ -4,8 +4,8 @@ from datetime import datetime
 
 from rich.text import Text
 
+from ..reactive import Reactive
 from ..widget import Widget
-from ..reactive import Reactive, watch
 
 
 class HeaderIcon(Widget):
@@ -133,5 +133,5 @@ class Header(Widget):
         def set_sub_title(sub_title: str) -> None:
             self.query_one(HeaderTitle).sub_text = sub_title
 
-        watch(self.app, "title", set_title)
+        self.watch(self.app, "title", set_title)
-        watch(self.app, "sub_title", set_sub_title)
+        self.watch(self.app, "sub_title", set_sub_title)

src/textual/widgets/_input.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
-from typing import ClassVar
 
 import re
+from typing import ClassVar
 
 from rich.cells import cell_len, get_character_cell_size
 from rich.console import Console, ConsoleOptions, RenderableType, RenderResult

src/textual/widgets/_list_view.py

@@ -1,4 +1,5 @@
 from __future__ import annotations
+
 from typing import ClassVar
 
 from textual.await_remove import AwaitRemove

src/textual/widgets/_placeholder.py

@@ -7,8 +7,7 @@ from typing_extensions import Literal
 from .. import events
 from ..css._error_tools import friendly_list
 from ..reactive import Reactive, reactive
-from ..widget import Widget, RenderResult
+from ..widget import RenderResult, Widget
-
 
 PlaceholderVariant = Literal["default", "size", "text"]
 _VALID_PLACEHOLDER_VARIANTS_ORDERED: list[PlaceholderVariant] = [

src/textual/widgets/_pretty.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from typing import Any
+
 from rich.pretty import Pretty as PrettyRenderable
 
 from ..widget import Widget

src/textual/widgets/_switch.py

@@ -8,16 +8,16 @@ from ..binding import Binding, BindingType
 from ..geometry import Size
 from ..message import Message
 from ..reactive import reactive
-from ..widget import Widget
 from ..scrollbar import ScrollBarRender
+from ..widget import Widget
 
 
-class Checkbox(Widget, can_focus=True):
+class Switch(Widget, can_focus=True):
-    """A checkbox widget that represents a boolean value.
+    """A switch widget that represents a boolean value.
 
-    Can be toggled by clicking on it or through its [bindings][textual.widgets.Checkbox.BINDINGS].
+    Can be toggled by clicking on it or through its [bindings][textual.widgets.Switch.BINDINGS].
 
-    The checkbox widget also contains [component classes][textual.widgets.Checkbox.COMPONENT_CLASSES]
+    The switch widget also contains [component classes][textual.widgets.Switch.COMPONENT_CLASSES]
     that enable more customization.
     """
 
@@ -27,20 +27,20 @@ class Checkbox(Widget, can_focus=True):
     """
     | Key(s) | Description |
     | :- | :- |
-    | enter,space | Toggle the checkbox status. |
+    | enter,space | Toggle the switch state. |
     """
 
     COMPONENT_CLASSES: ClassVar[set[str]] = {
-        "checkbox--switch",
+        "switch--switch",
     }
     """
     | Class | Description |
     | :- | :- |
-    | `checkbox--switch` | Targets the switch of the checkbox. |
+    | `switch--switch` | Targets the switch of the switch. |
     """
 
     DEFAULT_CSS = """
-    Checkbox {
+    Switch {
         border: tall transparent;
         background: $panel;
         height: auto;
@@ -48,49 +48,49 @@ class Checkbox(Widget, can_focus=True):
         padding: 0 2;
     }
 
-    Checkbox > .checkbox--switch {
+    Switch > .switch--switch {
         background: $panel-darken-2;
         color: $panel-lighten-2;
     }
 
-    Checkbox:hover {
+    Switch:hover {
         border: tall $background;
     }
 
-    Checkbox:focus {
+    Switch:focus {
         border: tall $accent;
     }
 
-    Checkbox.-on {
+    Switch.-on {
 
     }
 
-    Checkbox.-on > .checkbox--switch {
+    Switch.-on > .switch--switch {
         color: $success;
     }
     """
 
     value = reactive(False, init=False)
-    """The value of the checkbox; `True` for on and `False` for off."""
+    """The value of the switch; `True` for on and `False` for off."""
 
     slider_pos = reactive(0.0)
     """The position of the slider."""
 
     class Changed(Message, bubble=True):
-        """Posted when the status of the checkbox changes.
+        """Posted when the status of the switch changes.
 
-        Can be handled using `on_checkbox_changed` in a subclass of `Checkbox`
+        Can be handled using `on_switch_changed` in a subclass of `Switch`
         or in a parent widget in the DOM.
 
         Attributes:
-            value: The value that the checkbox was changed to.
+            value: The value that the switch was changed to.
-            input: The `Checkbox` widget that was changed.
+            input: The `Switch` widget that was changed.
         """
 
-        def __init__(self, sender: Checkbox, value: bool) -> None:
+        def __init__(self, sender: Switch, value: bool) -> None:
             super().__init__(sender)
             self.value: bool = value
-            self.input: Checkbox = sender
+            self.input: Switch = sender
 
     def __init__(
         self,
@@ -101,14 +101,14 @@ class Checkbox(Widget, can_focus=True):
         id: str | None = None,
         classes: str | None = None,
     ):
-        """Initialise the checkbox.
+        """Initialise the switch.
 
         Args:
-            value: The initial value of the checkbox. Defaults to False.
+            value: The initial value of the switch. Defaults to False.
-            animate: True if the checkbox should animate when toggled. Defaults to True.
+            animate: True if the switch should animate when toggled. Defaults to True.
-            name: The name of the checkbox.
+            name: The name of the switch.
-            id: The ID of the checkbox in the DOM.
+            id: The ID of the switch in the DOM.
-            classes: The CSS classes of the checkbox.
+            classes: The CSS classes of the switch.
         """
         super().__init__(name=name, id=id, classes=classes)
         if value:
@@ -128,7 +128,7 @@ class Checkbox(Widget, can_focus=True):
         self.set_class(slider_pos == 1, "-on")
 
     def render(self) -> RenderableType:
-        style = self.get_component_rich_style("checkbox--switch")
+        style = self.get_component_rich_style("switch--switch")
         return ScrollBarRender(
             virtual_size=100,
             window_size=50,
@@ -150,6 +150,6 @@ class Checkbox(Widget, can_focus=True):
         self.toggle()
 
     def toggle(self) -> None:
-        """Toggle the checkbox value. As a result of the value changing,
+        """Toggle the switch value. As a result of the value changing,
-        a Checkbox.Changed message will be posted."""
+        a Switch.Changed message will be posted."""
         self.value = not self.value

src/textual/widgets/_welcome.py

@@ -1,10 +1,10 @@
-from ..app import ComposeResult
-from ._static import Static
-from ._button import Button
-from ..containers import Container
-
 from rich.markdown import Markdown
 
+from ..app import ComposeResult
+from ..containers import Container
+from ._button import Button
+from ._static import Static
+
 WELCOME_MD = """\
 # Welcome!
 

src/textual/widgets/tabs.py

@@ -7,11 +7,11 @@ from typing import Iterable
 from rich.cells import cell_len
 from rich.console import Console, ConsoleOptions, RenderableType, RenderResult
 from rich.segment import Segment
-from rich.style import StyleType, Style
+from rich.style import Style, StyleType
 from rich.text import Text
 
 from textual import events
-from textual._layout_resolve import layout_resolve, Edge
+from textual._layout_resolve import Edge, layout_resolve
 from textual.keys import Keys
 from textual.reactive import Reactive
 from textual.renderables.text_opacity import TextOpacity

tests/css/test_help_text.py

@@ -2,17 +2,17 @@ import pytest
 
 from tests.utilities.render import render
 from textual.css._help_text import (
-    spacing_wrong_number_of_values_help_text,
-    spacing_invalid_value_help_text,
-    scalar_help_text,
-    string_enum_help_text,
-    color_property_help_text,
-    border_property_help_text,
-    layout_property_help_text,
-    fractional_property_help_text,
-    offset_property_help_text,
     align_help_text,
+    border_property_help_text,
+    color_property_help_text,
+    fractional_property_help_text,
+    layout_property_help_text,
+    offset_property_help_text,
     offset_single_axis_help_text,
+    scalar_help_text,
+    spacing_invalid_value_help_text,
+    spacing_wrong_number_of_values_help_text,
+    string_enum_help_text,
     style_flags_property_help_text,
 )
 

tests/css/test_parse.py

@@ -8,7 +8,7 @@ from textual.css.parse import substitute_references
 from textual.css.scalar import Scalar, Unit
 from textual.css.stylesheet import Stylesheet, StylesheetParseError
 from textual.css.tokenize import tokenize
-from textual.css.tokenizer import Token, ReferencedBy
+from textual.css.tokenizer import ReferencedBy, Token
 from textual.css.transition import Transition
 from textual.geometry import Spacing
 from textual.layouts.vertical import VerticalLayout

tests/css/test_styles.py

@@ -1,13 +1,12 @@
 from decimal import Decimal
 
 import pytest
-
 from rich.style import Style
 
 from textual.color import Color
 from textual.css.errors import StyleValueError
 from textual.css.scalar import Scalar, Unit
-from textual.css.styles import Styles, RenderStyles
+from textual.css.styles import RenderStyles, Styles
 from textual.dom import DOMNode
 from textual.widget import Widget
 

tests/devtools/__init__.py

@@ -11,6 +11,4 @@ _WINDOWS = sys.platform == "win32"
 # and the error messages suggest the event loop is being shutdown before async fixture
 # teardown code has finished running. These are very rare, but are much more of an issue on
 # CI since they can delay builds that have passed locally.
-pytestmark = pytest.mark.skipif(
+pytestmark = pytest.mark.skipif(_MACOS_CI or _WINDOWS, reason="Issue #411")
-    _MACOS_CI or _WINDOWS, reason="Issue #411"
-)