Return 'self' in some widget verb methods.

CHANGELOG.md

@@ -17,6 +17,16 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Breaking change: changed default behaviour of `Vertical` (see `VerticalScroll`) https://github.com/Textualize/textual/issues/1957
 - The default `overflow` style for `Horizontal` was changed to `hidden hidden` https://github.com/Textualize/textual/issues/1957
 - `DirectoryTree` also accepts `pathlib.Path` objects as the path to list https://github.com/Textualize/textual/issues/1438
+- Some widget methods now return `self` instead of `None` https://github.com/Textualize/textual/pull/2102:
+  - `Widget`: `refresh`, `focus`, `reset_focus`
+  - `Button.press`
+  - `DataTable`: `clear`, `refresh_coordinate`, `refresh_row`, `refresh_column`, `sort`
+  - `Placehoder.cycle_variant`
+  - `Switch.toggle`
+  - `Tabs.clear`
+  - `TextLog`: `write`, `clear`
+  - `TreeNode`: `expand`, `expand_all`, `collapse`, `collapse_all`, `toggle`, `toggle_all`
+  - `Tree`: `clear`, `reset`
 
 ### Removed
 

src/textual/dom.py

@@ -42,7 +42,7 @@
     from .css.query import DOMQuery, QueryType
     from .screen import Screen
     from .widget import Widget
-    from typing_extensions import TypeAlias
+    from typing_extensions import Self, TypeAlias
 
 from typing_extensions import Literal
 
@@ -950,5 +950,5 @@ def has_pseudo_class(self, *class_names: str) -> bool:
         has_pseudo_classes = self.pseudo_classes.issuperset(class_names)
         return has_pseudo_classes
 
-    def refresh(self, *, repaint: bool = True, layout: bool = False) -> None:
-        pass
+    def refresh(self, *, repaint: bool = True, layout: bool = False) -> Self:
+        return self

src/textual/widget.py

@@ -2542,7 +2542,7 @@ def refresh(
         *regions: Region,
         repaint: bool = True,
         layout: bool = False,
-    ) -> None:
+    ) -> Self:
         """Initiate a refresh of the widget.
 
         This method sets an internal flag to perform a refresh, which will be done on the
@@ -2558,8 +2558,11 @@ def refresh(
 
         Args:
             *regions: Additional screen regions to mark as dirty.
-            repaint: Repaint the widget (will call render() again). Defaults to True.
-            layout: Also layout widgets in the view. Defaults to False.
+            repaint: Repaint the widget (will call render() again).
+            layout: Also layout widgets in the view.
+
+        Returns:
+            The `Widget` instance.
         """
         if layout and not self._layout_required:
             self._layout_required = True
@@ -2577,6 +2580,7 @@ def refresh(
             self._repaint_required = True
 
         self.check_idle()
+        return self
 
     def remove(self) -> AwaitRemove:
         """Remove the Widget from the DOM (effectively deleting it).
@@ -2658,12 +2662,14 @@ def _check_refresh(self) -> None:
                     self._layout_required = False
                     screen.post_message(messages.Layout())
 
-    def focus(self, scroll_visible: bool = True) -> None:
+    def focus(self, scroll_visible: bool = True) -> Self:
         """Give focus to this widget.
 
         Args:
-            scroll_visible: Scroll parent to make this widget
-                visible. Defaults to True.
+            scroll_visible: Scroll parent to make this widget visible.
+
+        Returns:
+            The `Widget` instance.
         """
 
         def set_focus(widget: Widget):
@@ -2674,13 +2680,19 @@ def set_focus(widget: Widget):
                 pass
 
         self.app.call_later(set_focus, self)
+        return self
+
+    def reset_focus(self) -> Self:
+        """Reset the focus (move it to the next available widget).
 
-    def reset_focus(self) -> None:
-        """Reset the focus (move it to the next available widget)."""
+        Returns:
+            The `Widget` instance.
+        """
         try:
             self.screen._reset_focus(self)
         except NoScreen:
             pass
+        return self
 
     def capture_mouse(self, capture: bool = True) -> None:
         """Capture (or release) the mouse.

src/textual/widgets/_button.py

@@ -1,11 +1,10 @@
 from __future__ import annotations
 
 from functools import partial
-from typing import cast
 
 import rich.repr
 from rich.text import Text, TextType
-from typing_extensions import Literal
+from typing_extensions import Literal, Self
 
 from .. import events
 from ..css._error_tools import friendly_list
@@ -233,14 +232,18 @@ async def _on_click(self, event: events.Click) -> None:
         event.stop()
         self.press()
 
-    def press(self) -> None:
-        """Respond to a button press."""
+    def press(self) -> Self:
+        """Respond to a button press.
+
+        Returns:
+            The button instance."""
         if self.disabled or not self.display:
-            return
+            return self
         # Manage the "active" effect:
         self._start_active_affect()
         # ...and let other components know that we've just been clicked:
         self.post_message(Button.Pressed(self))
+        return self
 
     def _start_active_affect(self) -> None:
         """Start a small animation to show the button was clicked."""

src/textual/widgets/_data_table.py

@@ -13,7 +13,7 @@
 from rich.segment import Segment
 from rich.style import Style
 from rich.text import Text, TextType
-from typing_extensions import Literal, TypeAlias
+from typing_extensions import Literal, Self, TypeAlias
 
 from .. import events
 from .._cache import LRUCache
@@ -1156,11 +1156,14 @@ def _get_column_region(self, column_index: int) -> Region:
         full_column_region = Region(x, 0, width, height)
         return full_column_region
 
-    def clear(self, columns: bool = False) -> None:
+    def clear(self, columns: bool = False) -> Self:
         """Clear the table.
 
         Args:
-            columns: Also clear the columns. Defaults to False.
+            columns: Also clear the columns.
+
+        Returns:
+            The `DataTable` instance.
         """
         self._clear_caches()
         self._y_offsets.clear()
@@ -1176,6 +1179,7 @@ def clear(self, columns: bool = False) -> None:
         self._label_column = Column(self._label_column_key, Text(), auto_width=True)
         self._labelled_row_exists = False
         self.refresh()
+        return self
 
     def add_column(
         self, label: TextType, *, width: int | None = None, key: str | None = None
@@ -1333,49 +1337,66 @@ def on_idle(self) -> None:
             self._updated_cells.clear()
             self._update_column_widths(updated_columns)
 
-    def refresh_coordinate(self, coordinate: Coordinate) -> None:
+    def refresh_coordinate(self, coordinate: Coordinate) -> Self:
         """Refresh the cell at a coordinate.
 
         Args:
             coordinate: The coordinate to refresh.
+
+        Returns:
+            The `DataTable` instance.
         """
         if not self.is_valid_coordinate(coordinate):
-            return
+            return self
         region = self._get_cell_region(coordinate)
         self._refresh_region(region)
+        return self
 
-    def refresh_row(self, row_index: int) -> None:
+    def refresh_row(self, row_index: int) -> Self:
         """Refresh the row at the given index.
 
         Args:
             row_index: The index of the row to refresh.
+
+        Returns:
+            The `DataTable` instance.
         """
         if not self.is_valid_row_index(row_index):
-            return
+            return self
 
         region = self._get_row_region(row_index)
         self._refresh_region(region)
+        return self
 
-    def refresh_column(self, column_index: int) -> None:
+    def refresh_column(self, column_index: int) -> Self:
         """Refresh the column at the given index.
 
         Args:
             column_index: The index of the column to refresh.
+
+        Returns:
+            The `DataTable` instance.
         """
         if not self.is_valid_column_index(column_index):
-            return
+            return self
 
         region = self._get_column_region(column_index)
         self._refresh_region(region)
+        return self
+
+    def _refresh_region(self, region: Region) -> Self:
+        """Refresh a region of the DataTable, if it's visible within the window.
+
+        This method will translate the region to account for scrolling.
 
-    def _refresh_region(self, region: Region) -> None:
-        """Refresh a region of the DataTable, if it's visible within
-        the window. This method will translate the region to account
-        for scrolling."""
+        Returns:
+            The `DataTable` instance.
+        """
         if not self.window_region.overlaps(region):
-            return
+            return self
         region = region.translate(-self.scroll_offset)
         self.refresh(region)
+        return self
 
     def is_valid_row_index(self, row_index: int) -> bool:
         """Return a boolean indicating whether the row_index is within table bounds.
@@ -1839,12 +1860,15 @@ def sort(
         self,
         *columns: ColumnKey | str,
         reverse: bool = False,
-    ) -> None:
-        """Sort the rows in the DataTable by one or more column keys.
+    ) -> Self:
+        """Sort the rows in the `DataTable` by one or more column keys.
 
         Args:
             columns: One or more columns to sort by the values in.
             reverse: If True, the sort order will be reversed.
+
+        Returns:
+            The `DataTable` instance.
         """
 
         def sort_by_column_keys(
@@ -1862,6 +1886,7 @@ def sort_by_column_keys(
         )
         self._update_count += 1
         self.refresh()
+        return self
 
     def _scroll_cursor_into_view(self, animate: bool = False) -> None:
         """When the cursor is at a boundary of the DataTable and moves out

src/textual/widgets/_placeholder.py

@@ -5,7 +5,7 @@
 from itertools import cycle
 
 from rich.console import RenderableType
-from typing_extensions import Literal
+from typing_extensions import Literal, Self
 
 from .. import events
 from ..css._error_tools import friendly_list
@@ -132,9 +132,14 @@ def render(self) -> RenderableType:
         """
         return self._renderables[self.variant]
 
-    def cycle_variant(self) -> None:
-        """Get the next variant in the cycle."""
+    def cycle_variant(self) -> Self:
+        """Get the next variant in the cycle.
+
+        Returns:
+            The `Placeholder` instance.
+        """
         self.variant = next(self._variants_cycle)
+        return self
 
     def watch_variant(
         self, old_variant: PlaceholderVariant, variant: PlaceholderVariant

src/textual/widgets/_switch.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import ClassVar
+from typing import TYPE_CHECKING, ClassVar
 
 from rich.console import RenderableType
 
@@ -11,6 +11,9 @@
 from ..scrollbar import ScrollBarRender
 from ..widget import Widget
 
+if TYPE_CHECKING:
+    from typing_extensions import Self
+
 
 class Switch(Widget, can_focus=True):
     """A switch widget that represents a boolean value.
@@ -158,10 +161,14 @@ def action_toggle(self) -> None:
         """Toggle the state of the switch."""
         self.toggle()
 
-    def toggle(self) -> None:
+    def toggle(self) -> Self:
         """Toggle the switch value.
 
         As a result of the value changing, a `Switch.Changed` message will
         be posted.
+
+        Returns:
+            The `Switch` instance.
         """
         self.value = not self.value
+        return self

src/textual/widgets/_tabs.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import ClassVar
+from typing import TYPE_CHECKING, ClassVar
 
 import rich.repr
 from rich.style import Style
@@ -18,6 +18,9 @@
 from ..widget import Widget
 from ..widgets import Static
 
+if TYPE_CHECKING:
+    from typing_extensions import Self
+
 
 class Underline(Widget):
     """The animated underline beneath tabs."""
@@ -316,13 +319,18 @@ async def refresh_active() -> None:
 
             self.call_after_refresh(refresh_active)
 
-    def clear(self) -> None:
-        """Clear all the tabs."""
+    def clear(self) -> Self:
+        """Clear all the tabs.
+
+        Returns:
+            The `Tabs` instance.
+        """
         underline = self.query_one(Underline)
         underline.highlight_start = 0
         underline.highlight_end = 0
         self.query("#tabs-list > Tab").remove()
         self.post_message(self.Cleared(self))
+        return self
 
     def remove_tab(self, tab_or_id: Tab | str | None) -> None:
         """Remove a tab.