add inherited bindings

CHANGELOG.md

@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Support lazy-instantiated Screens (callables in App.SCREENS) https://github.com/Textualize/textual/pull/1185
 - Display of keys in footer has more sensible defaults https://github.com/Textualize/textual/pull/1213
 - Add App.get_key_display, allowing custom key_display App-wide https://github.com/Textualize/textual/pull/1213
+- Added "inherited bindings" -- BINDINGS classvar will be merged with base classes, unless inherit_bindings is set to False
 
 ### Changed
 

src/textual/_compositor.py

@@ -458,7 +458,6 @@ def add_widget(
 
         # Add top level (root) widget
         add_widget(root, size.region, size.region, ((0,),), layer_order, size.region)
-        root.log(map)
         return map, widgets
 
     @property

src/textual/dom.py

@@ -22,7 +22,7 @@
 
 from ._context import NoActiveAppError
 from ._node_list import NodeList
-from .binding import Bindings, BindingType
+from .binding import Binding, Bindings, BindingType
 from .color import BLACK, WHITE, Color
 from .css._error_tools import friendly_list
 from .css.constants import VALID_DISPLAY, VALID_VISIBILITY
@@ -97,9 +97,16 @@ class DOMNode(MessagePump):
 
     # True if this node inherits the CSS from the base class.
     _inherit_css: ClassVar[bool] = True
+
+    # True to inherit bindings from base class
+    _inherit_bindings: ClassVar[bool] = True
+
     # List of names of base classes that inherit CSS
     _css_type_names: ClassVar[frozenset[str]] = frozenset()
 
+    # Generated list of bindings
+    _merged_bindings: ClassVar[Bindings] | None = None
+
     def __init__(
         self,
         *,
@@ -127,7 +134,7 @@ def __init__(
         self._auto_refresh: float | None = None
         self._auto_refresh_timer: Timer | None = None
         self._css_types = {cls.__name__ for cls in self._css_bases(self.__class__)}
-        self._bindings = Bindings(self.BINDINGS)
+        self._bindings = self._merged_bindings or Bindings()
         self._has_hover_style: bool = False
         self._has_focus_within: bool = False
 
@@ -152,12 +159,16 @@ def _automatic_refresh(self) -> None:
         """Perform an automatic refresh (set with auto_refresh property)."""
         self.refresh()
 
-    def __init_subclass__(cls, inherit_css: bool = True) -> None:
+    def __init_subclass__(
+        cls, inherit_css: bool = True, inherit_bindings: bool = True
+    ) -> None:
         super().__init_subclass__()
         cls._inherit_css = inherit_css
+        cls._inherit_bindings = inherit_bindings
         css_type_names: set[str] = set()
         for base in cls._css_bases(cls):
             css_type_names.add(base.__name__)
+        cls._merged_bindings = cls._merge_bindings()
         cls._css_type_names = frozenset(css_type_names)
 
     def get_component_styles(self, name: str) -> RenderStyles:
@@ -205,6 +216,25 @@ def _css_bases(cls, base: Type[DOMNode]) -> Iterator[Type[DOMNode]]:
             else:
                 break
 
+    @classmethod
+    def _merge_bindings(cls) -> Bindings:
+        """Merge bindings from base classes.
+
+        Returns:
+            Bindings: Merged bindings.
+        """
+        bindings: list[Bindings] = []
+
+        for base in reversed(cls.__mro__):
+            if issubclass(base, DOMNode):
+                if not base._inherit_bindings:
+                    bindings.clear()
+                bindings.append(Bindings(base.BINDINGS))
+        keys = {}
+        for bindings_ in bindings:
+            keys.update(bindings_.keys)
+        return Bindings(keys.values())
+
     def _post_register(self, app: App) -> None:
         """Called when the widget is registered
 

src/textual/widget.py

@@ -174,6 +174,12 @@ class Widget(DOMNode):
     BINDINGS = [
         Binding("up", "scroll_up", "Scroll Up", show=False),
         Binding("down", "scroll_down", "Scroll Down", show=False),
+        Binding("left", "scroll_left", "Scroll Up", show=False),
+        Binding("right", "scroll_right", "Scroll Right", show=False),
+        Binding("home", "scroll_home", "Scroll Home", show=False),
+        Binding("end", "scroll_end", "Scroll End", show=False),
+        Binding("pageup", "page_up", "Page Up", show=False),
+        Binding("pagedown", "page_down", "Page Down", show=False),
     ]
 
     DEFAULT_CSS = """
@@ -1816,9 +1822,13 @@ def __init_subclass__(
         can_focus: bool | None = None,
         can_focus_children: bool | None = None,
         inherit_css: bool = True,
+        inherit_bindings: bool = True,
     ) -> None:
         base = cls.__mro__[0]
-        super().__init_subclass__(inherit_css=inherit_css)
+        super().__init_subclass__(
+            inherit_css=inherit_css,
+            inherit_bindings=inherit_bindings,
+        )
         if issubclass(base, Widget):
             cls.can_focus = base.can_focus if can_focus is None else can_focus
             cls.can_focus_children = (
@@ -2345,53 +2355,21 @@ def _on_hide(self, event: events.Hide) -> None:
     def _on_scroll_to_region(self, message: messages.ScrollToRegion) -> None:
         self.scroll_to_region(message.region, animate=True)
 
-    def _key_home(self) -> bool:
+    def action_scroll_home(self) -> None:
         if self._allow_scroll:
             self.scroll_home()
-            return True
-        return False
 
-    def _key_end(self) -> bool:
+    def action_scroll_end(self) -> None:
         if self._allow_scroll:
             self.scroll_end()
-            return True
-        return False
 
-    def _key_left(self) -> bool:
+    def action_scroll_left(self) -> None:
         if self.allow_horizontal_scroll:
             self.scroll_left()
-            return True
-        return False
 
-    def _key_right(self) -> bool:
+    def action_scroll_right(self) -> None:
         if self.allow_horizontal_scroll:
             self.scroll_right()
-            return True
-        return False
-
-    # def _key_down(self) -> bool:
-    #     if self.allow_vertical_scroll:
-    #         self.scroll_down()
-    #         return True
-    #     return False
-
-    # def _key_up(self) -> bool:
-    #     if self.allow_vertical_scroll:
-    #         self.scroll_up()
-    #         return True
-    #     return False
-
-    def _key_pagedown(self) -> bool:
-        if self.allow_vertical_scroll:
-            self.scroll_page_down()
-            return True
-        return False
-
-    def _key_pageup(self) -> bool:
-        if self.allow_vertical_scroll:
-            self.scroll_page_up()
-            return True
-        return False
 
     def action_scroll_up(self) -> None:
         if self.allow_vertical_scroll:
@@ -2400,3 +2378,11 @@ def action_scroll_up(self) -> None:
     def action_scroll_down(self) -> None:
         if self.allow_vertical_scroll:
             self.scroll_down()
+
+    def action_page_down(self) -> None:
+        if self.allow_vertical_scroll:
+            self.scroll_page_down()
+
+    def action_page_up(self) -> None:
+        if self.allow_vertical_scroll:
+            self.scroll_page_up()

src/textual/widgets/_tree.py

@@ -26,7 +26,7 @@
 TreeDataType = TypeVar("TreeDataType")
 EventTreeDataType = TypeVar("EventTreeDataType")
 
-LineCacheKey: TypeAlias = tuple[int | tuple[int, ...], ...]
+LineCacheKey: TypeAlias = tuple[int | tuple, ...]
 
 TOGGLE_STYLE = Style.from_meta({"toggle": True})
 
@@ -199,9 +199,9 @@ def add(
 class Tree(Generic[TreeDataType], ScrollView, can_focus=True):
 
     BINDINGS = [
+        Binding("enter", "select_cursor", "Select", show=False),
         Binding("up", "cursor_up", "Cursor Up", show=False),
         Binding("down", "cursor_down", "Cursor Down", show=False),
-        Binding("enter", "select_cursor", "Select", show=False),
     ]
 
     DEFAULT_CSS = """
@@ -334,6 +334,10 @@ def cursor_node(self) -> TreeNode[TreeDataType] | None:
         """TreeNode | Node: The currently selected node, or ``None`` if no selection."""
         return self._cursor_node
 
+    @property
+    def last_line(self) -> int:
+        return len(self._tree_lines) - 1
+
     def process_label(self, label: TextType):
         """Process a str or Text in to a label. Maybe overridden in a subclass to change modify how labels are rendered.
 
@@ -797,15 +801,37 @@ def _on_styles_updated(self) -> None:
 
     def action_cursor_up(self) -> None:
         if self.cursor_line == -1:
-            self.cursor_line = len(self._tree_lines) - 1
+            self.cursor_line = self.last_line
         else:
             self.cursor_line -= 1
         self.scroll_to_line(self.cursor_line)
 
     def action_cursor_down(self) -> None:
+        if self.cursor_line == -1:
+            self.cursor_line = 0
         self.cursor_line += 1
         self.scroll_to_line(self.cursor_line)
 
+    def action_page_down(self) -> None:
+        if self.cursor_line == -1:
+            self.cursor_line = 0
+        self.cursor_line += self.scrollable_content_region.height - 1
+        self.scroll_to_line(self.cursor_line)
+
+    def action_page_up(self) -> None:
+        if self.cursor_line == -1:
+            self.cursor_line = self.last_line
+        self.cursor_line -= self.scrollable_content_region.height - 1
+        self.scroll_to_line(self.cursor_line)
+
+    def action_scroll_home(self) -> None:
+        self.cursor_line = 0
+        self.scroll_to_line(self.cursor_line)
+
+    def action_scroll_end(self) -> None:
+        self.cursor_line = self.last_line
+        self.scroll_to_line(self.cursor_line)
+
     def action_select_cursor(self) -> None:
         try:
             line = self._tree_lines[self.cursor_line]