feat: unindent on backspace within leading whitespace

crates/edit/src/buffer/mod.rs

@@ -2472,6 +2472,37 @@ impl TextBuffer {
         self.set_selection(None);
     }
 
+    pub fn backspace_unindent(&mut self) -> bool {
+        if self.selection.is_some() || self.cursor.offset == 0 {
+            return false;
+        }
+
+        let line_start = self.goto_line_start(self.cursor, self.cursor.logical_pos.y);
+        let (indent_chars, _) = self.measure_indent_internal(line_start.offset, CoordType::MAX);
+
+        let chars_from_line_start = self.cursor.logical_pos.x;
+        if chars_from_line_start == 0 || chars_from_line_start > indent_chars {
+            return false;
+        }
+
+        let cursor_column = self.cursor.column;
+        if cursor_column == 0 {
+            return false;
+        }
+
+        let prev_column = self.tab_size_prev_column(cursor_column);
+        let (prev_chars, _) = self.measure_indent_internal(line_start.offset, prev_column);
+
+        let chars_to_delete = chars_from_line_start - prev_chars;
+        if chars_to_delete <= 0 {
+            return false;
+        }
+
+        self.delete(CursorMovement::Grapheme, -chars_to_delete);
+
+        true
+    }
+
     /// Returns the logical position of the first character on this line.
     /// Return `.x == 0` if there are no non-whitespace characters.
     pub fn indent_end_logical_pos(&self) -> Point {

crates/edit/src/tui.rs

@@ -2365,12 +2365,13 @@ impl<'a> Context<'a, '_> {
 
             match key {
                 vk::BACK => {
-                    let granularity = if modifiers == kbmod::CTRL {
-                        CursorMovement::Word
+                    if modifiers == kbmod::CTRL {
+                        tb.delete(CursorMovement::Word, -1);
+                    } else if modifiers == kbmod::NONE && tb.backspace_unindent() {
+                        return false;
                     } else {
-                        CursorMovement::Grapheme
-                    };
-                    tb.delete(granularity, -1);
+                        tb.delete(CursorMovement::Grapheme, -1);
+                    }
                 }
                 vk::TAB => {
                     if single_line {