Add tree rotations to Expr

1 files changed, 21 insertions, 0 deletions

diff --git a/mdpoly/abc.py b/mdpoly/abc.py
index 14026d6..0f51bbc 100644
--- a/mdpoly/abc.py
+++ b/mdpoly/abc.py
@@ -171,6 +171,27 @@ class Expr(ABC):
 
         return replace_all(self)
 
+    def rotate_left(self) -> Expr:
+        """ Perform a left tree rotation. """
+        root = copy(self) # current root
+        pivot = copy(self.right) # new parent
+
+        root.right = pivot.left
+        pivot.left = root
+        
+        return pivot
+
+    def rotate_right(self) -> Expr:
+        """ Perform a right tree rotation. """
+        root = copy(self) # current root
+        pivot = copy(root.left) # new parent
+
+        root.left = pivot.right
+        pivot.right = root
+        
+        return pivot
+
+
     # --- Private methods ---
 
     @staticmethod