Added Target-Action

MathPad/MPExpressionView.h

@@ -25,4 +25,7 @@
 @property (nonatomic, getter = isEditable) BOOL editable;
 @property (nonatomic, strong) MPRangePath *selection;
 
+@property (nonatomic, weak) id target;
+@property (nonatomic) SEL action;
+
 @end

MathPad/MPExpressionView.m

@@ -275,6 +275,15 @@
     }
 }
 
+- (void)insertNewline:(id)sender
+{
+    if (self.target && self.action) {
+        [self.target performSelector:self.action
+                          withObject:self
+                          afterDelay:0.0];
+    }
+}
+
 - (void)moveRight:(id)sender
 {
     if (self.selection.length > 0) {