Stub out KeyboardNavigation

crates/ui/src/components/keyboard_navigation.rs

@@ -0,0 +1,59 @@
+use gpui::{Focusable, actions};
+
+actions!(
+    keyboard_navigation,
+    [NextRow, PreviousRow, NextColumn, PreviousColumn]
+);
+
+/// Implement this trait to enable grid-like keyboard navigation for a layout.
+///
+/// This trait allows you to navigate through a layout of rows with mixed column
+/// lengths. In example, a layout might have rows with 5, 1 and 3 columns.
+///
+/// Moving up or down between rows will focus the first element in the next or previous row.
+/// Moving left or right between columns will focus the next or previous element in the same row.
+///
+/// Wrapping can be enabled via `vertical_wrapping` and `horizontal_wrapping` respectively.
+pub trait KeyboardNavigation: Focusable {
+    fn has_focus(&self) -> bool;
+    /// The focused row. Always has a value to allow for "focused inactive" states.
+    fn focused_row(&self) -> usize;
+    /// The focused column. Always has a value to allow for "focused inactive" states.
+    fn focused_column(&self) -> usize;
+    /// Focus the first focusable element in the layout.
+    fn focus_first(&self);
+    /// Focus the next row, wrapping back to the first row if necessary.
+    ///
+    /// Is a no-op if wrapping is not enabled.
+    fn focus_next_row(&self);
+    /// Focus the previous row, wrapping back to the last row if necessary.
+    ///
+    /// Is a no-op if wrapping is not enabled.
+    fn focus_previous_row(&self);
+    /// Focus the next column, wrapping back to the first column if necessary.
+    ///
+    /// Is a no-op if wrapping is not enabled.
+    fn focus_next_column(&self);
+    /// Focus the previous column, wrapping back to the last column if necessary.
+    ///
+    /// Is a no-op if wrapping is not enabled.
+    fn focus_previous_column(&self);
+    /// Focus the row at the given index.
+    fn focus_row_index(&self, index: usize);
+    /// Focus the column at the given index.
+    fn focus_column_index(&self, ix: usize);
+    /// When reaching the last row, should moving down wrap
+    /// back to the first row, and vice versa?
+    fn vertical_wrap(&self) -> bool {
+        false
+    }
+    /// When reaching the last column, should moving right wrap
+    /// back to the first column, and vice versa?
+    fn horizontal_wrap(&self) -> bool {
+        false
+    }
+}
+
+pub struct NavigationRow {}
+
+pub struct NavigationColumn {}