Inform when reaching undo/redo bounds (#981)

* Inform when reaching undo/redo bounds

* `Already at oldest change` when undo fails
* `Already at newest change` when redo fails

* Add missing `the`

1 files changed, 6 insertions, 4 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 02da4b7a..0d86143b 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -704,8 +704,8 @@ impl Document {
         success
     }
 
-    /// Undo the last modification to the [`Document`].
-    pub fn undo(&mut self, view_id: ViewId) {
+    /// Undo the last modification to the [`Document`]. Returns whether the undo was successful.
+    pub fn undo(&mut self, view_id: ViewId) -> bool {
         let mut history = self.history.take();
         let success = if let Some(transaction) = history.undo() {
             self.apply_impl(transaction, view_id)
@@ -718,10 +718,11 @@ impl Document {
             // reset changeset to fix len
             self.changes = ChangeSet::new(self.text());
         }
+        success
     }
 
-    /// Redo the last modification to the [`Document`].
-    pub fn redo(&mut self, view_id: ViewId) {
+    /// Redo the last modification to the [`Document`]. Returns whether the redo was sucessful.
+    pub fn redo(&mut self, view_id: ViewId) -> bool {
         let mut history = self.history.take();
         let success = if let Some(transaction) = history.redo() {
             self.apply_impl(transaction, view_id)
@@ -734,6 +735,7 @@ impl Document {
             // reset changeset to fix len
             self.changes = ChangeSet::new(self.text());
         }
+        success
     }
 
     pub fn savepoint(&mut self) {