feat: add smart_delete_backward command for improved smart pair handling

src/buffer/unicode.zig

@@ -38,6 +38,25 @@ pub fn control_code_to_unicode(code: u8) [:0]const u8 {
     };
 }
 
+pub const char_pairs = [_]struct { []const u8, []const u8 }{
+    .{ "\"", "\"" },
+    .{ "'", "'" },
+    .{ "(", ")" },
+    .{ "(", ")" },
+    .{ "[", "]" },
+    .{ "[", "]" },
+    .{ "{", "}" },
+    .{ "{", "}" },
+    .{ "‘", "’" },
+    .{ "‘", "’" },
+    .{ "“", "”" },
+    .{ "“", "”" },
+    .{ "‚", "‘" },
+    .{ "‚", "‘" },
+    .{ "«", "»" },
+    .{ "«", "»" },
+};
+
 fn raw_byte_to_utf8(cp: u8, buf: []u8) ![]const u8 {
     var utf16le: [1]u16 = undefined;
     const utf16le_as_bytes = std.mem.sliceAsBytes(utf16le[0..]);

src/keybind/builtin/flow.json

@@ -149,7 +149,7 @@
             ["escape", "cancel"],
             ["enter", "smart_insert_line"],
             ["delete", "delete_forward"],
-            ["backspace", "delete_backward"],
+            ["backspace", "smart_delete_backward"],
             ["left", "move_left"],
             ["right", "move_right"],
             ["up", "move_up"],

src/tui/editor.zig

@@ -2773,6 +2773,49 @@ pub const Editor = struct {
     }
     pub const delete_backward_meta = .{ .description = "Delete previous character" };
 
+    pub fn smart_delete_backward(self: *Self, _: Context) Result {
+        const b = try self.buf_for_update();
+        var all_stop = true;
+        var root = b.root;
+
+        for (self.cursels.items) |*cursel_| if (cursel_.*) |*cursel| {
+            if (cursel.selection) |_| {
+                root = self.delete_selection(root, cursel, b.allocator) catch continue;
+                all_stop = false;
+                continue;
+            }
+            with_selection_const(root, move_cursor_left, cursel, self.metrics) catch continue;
+
+            if (cursel.selection) |*sel| {
+                const egc_left, _, _ = sel.end.egc_at(root, self.metrics) catch {
+                    root = self.delete_selection(root, cursel, b.allocator) catch continue;
+                    all_stop = false;
+                    continue;
+                };
+                const egc_right, _, _ = sel.begin.egc_at(root, self.metrics) catch {
+                    root = self.delete_selection(root, cursel, b.allocator) catch continue;
+                    all_stop = false;
+                    continue;
+                };
+
+                for (Buffer.unicode.char_pairs) |pair| if (std.mem.eql(u8, egc_left, pair[0]) and std.mem.eql(u8, egc_right, pair[1])) {
+                    sel.begin.move_right(root, self.metrics) catch {};
+                    break;
+                };
+            }
+
+            root = self.delete_selection(root, cursel, b.allocator) catch continue;
+            all_stop = false;
+        };
+
+        if (all_stop)
+            return error.Stop;
+
+        try self.update_buf(root);
+        self.clamp();
+    }
+    pub const smart_delete_backward_meta = .{ .description = "Delete previous character (smart)" };
+
     pub fn delete_word_left(self: *Self, _: Context) Result {
         const b = try self.buf_for_update();
         const root = try self.delete_to(move_cursor_word_left_space, b.root, b.allocator);