diff --git a/src/formulate/AST.py b/src/formulate/AST.py
index d1a7ca6..d179c3f 100644
--- a/src/formulate/AST.py
+++ b/src/formulate/AST.py
@@ -186,6 +186,18 @@ def to_python(self):
                 return "np.exp(1)"
             case "e":
                 return "np.exp(1)"
+            case "max":
+                return f"root_max({self.arguments[0]})"
+            case "min":
+                return f"root_min({self.arguments[0]})"
+            case "sum":
+                return f"root_sum({self.arguments[0]})"
+            case "no_of_entries":
+                return f"root_length({self.arguments[0]})"
+            case "min_if":
+                return f"root_min_if({self.arguments[0]}, {self.arguments[1]})"
+            case "max_if":
+                return f"root_max_if({self.arguments[0]}, {self.arguments[1]})"
             case _ :
                 raise ValueError("Not a valid function!")
 
diff --git a/src/formulate/ttreeformula.py b/src/formulate/ttreeformula.py
index 8c0d7ff..bd2ed70 100644
--- a/src/formulate/ttreeformula.py
+++ b/src/formulate/ttreeformula.py
@@ -42,7 +42,7 @@
 func_name: CNAME | CNAME "::" func_name
 trailer: "(" [arglist] ")"
 arglist: expression ("," expression)* [","]
-CNAME: /[A-Za-z_]([A-Za-z0-9_]|\s*\.\s*)*/
+CNAME: /[A-Za-z_$]([A-Za-z0-9_$]|\s*\.\s*)*/
 
 %import common.NUMBER
 %import common.WS