3 files changed, 40 insertions, 13 deletions

diff --git a/crates/libeditor/src/code_actions.rs b/crates/libeditor/src/code_actions.rs
index 6e2c73f29..88c348436 100644
--- a/crates/libeditor/src/code_actions.rs
+++ b/crates/libeditor/src/code_actions.rs
@@ -10,7 +10,17 @@ use libsyntax2::{
     },
 };
 
-pub fn flip_comma<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce() -> Edit + 'a> {
+pub struct ActionResult {
+    pub edit: Edit,
+    pub cursor_position: CursorPosition,
+}
+
+pub enum CursorPosition {
+    Same,
+    Offset(TextUnit),
+}
+
+pub fn flip_comma<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce() -> ActionResult + 'a> {
     let syntax = file.syntax();
     let syntax = syntax.as_ref();
 
@@ -21,18 +31,27 @@ pub fn flip_comma<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce()
         let mut edit = EditBuilder::new();
         edit.replace(left.range(), right.text());
         edit.replace(right.range(), left.text());
-        edit.finish()
+        ActionResult {
+            edit: edit.finish(),
+            cursor_position: CursorPosition::Same,
+        }
     })
 }
 
-pub fn add_derive<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce() -> Edit + 'a> {
+pub fn add_derive<'a>(file: &'a File, offset: TextUnit) -> Option<impl FnOnce() -> ActionResult + 'a> {
     let syntax = file.syntax();
     let syntax = syntax.as_ref();
     let nominal = find_node::<ast::NominalDef<_>>(syntax, offset)?;
     Some(move || {
         let mut edit = EditBuilder::new();
-        edit.insert(nominal.syntax().range().start(), "#[derive()]\n".to_string());
-        edit.finish()
+        let node_start = nominal.syntax().range().start();
+        edit.insert(node_start, "#[derive()]\n".to_string());
+        ActionResult {
+            edit: edit.finish(),
+            cursor_position: CursorPosition::Offset(
+                node_start + TextUnit::of_str("#[derive(")
+            ),
+        }
     })
 }
 
diff --git a/crates/libeditor/src/edit.rs b/crates/libeditor/src/edit.rs
index 15a2a904f..3edd0809d 100644
--- a/crates/libeditor/src/edit.rs
+++ b/crates/libeditor/src/edit.rs
@@ -67,6 +67,21 @@ impl Edit {
         assert_eq!(buf.len(), total_len);
         buf
     }
+
+    pub fn apply_to_offset(&self, offset: TextUnit) -> Option<TextUnit> {
+        let mut res = offset;
+        for atom in self.atoms.iter() {
+            if atom.delete.start() >= offset {
+                break;
+            }
+            if offset < atom.delete.end() {
+                return None
+            }
+            res += TextUnit::of_str(&atom.insert);
+            res -= atom.delete.len();
+        }
+        Some(res)
+    }
 }
 
 impl AtomEdit {
diff --git a/crates/libeditor/src/lib.rs b/crates/libeditor/src/lib.rs
index 2c46ca45f..9e44f5d92 100644
--- a/crates/libeditor/src/lib.rs
+++ b/crates/libeditor/src/lib.rs
@@ -21,7 +21,7 @@ pub use self::{
     extend_selection::extend_selection,
     symbols::{StructureNode, file_structure, FileSymbol, file_symbols},
     edit::{EditBuilder, Edit, AtomEdit},
-    code_actions::{flip_comma, add_derive},
+    code_actions::{flip_comma, add_derive, ActionResult, CursorPosition},
 };
 
 #[derive(Debug)]
@@ -37,13 +37,6 @@ pub struct Diagnostic {
 }
 
 #[derive(Debug)]
-pub struct Symbol {
-    // pub parent: ???,
-    pub name: String,
-    pub range: TextRange,
-}
-
-#[derive(Debug)]
 pub struct Runnable {
     pub range: TextRange,
     pub kind: RunnableKind,