Removed Expression Tree Notification Methods

MathPad/MPExpression.m

@@ -50,14 +50,6 @@ NSString *MPDivisionOperator = @"/";
 
 #pragma mark Working With the Expression Tree
 
-- (void)functionSymbolChanged:(MPFunction *)symbol atLocalIndexPath:(NSIndexPath *)indexPath
-{
-    NSUInteger index = [_symbols indexOfObject:symbol];
-    if (index != NSNotFound) {
-        [self.parent childChanged:self atLocalIndexPath:[indexPath indexPathByAddingIndex:index]];
-    }
-}
-
 - (void)fixSymbols
 {
     _symbols = [self fixedSymbols:_symbols];
@@ -445,8 +437,12 @@ NSString *MPDivisionOperator = @"/";
     
     // Locate the position, split the symbols
     NSUInteger startIndex;
-    [self splitSymbolsAtLocation:range.location
-                  insertionIndex:&startIndex];
+    if ([self numberOfSymbols] == 0) {
+        startIndex = 0;
+    } else {
+        [self splitSymbolsAtLocation:range.location
+                      insertionIndex:&startIndex];
+    }
     
     // Perform the deletion
     if (range.length > 0) {