Great comment! Agreed. I'm a little afraid of that hack though and what it might do to a query optimizer. You're right that the callable system makes loops tri

Great comment! Agreed. I'm a little afraid of that hack though and what it might do to a query optimizer. You're right that the callable system makes loops tricky. Also, great point about the closing parens. We use python specifically to avoid them and to just use whitespace! In practice, I have done a mixed approach as you suggested. I used this iterative style with limited callable style embedded where that makes sense (everything just returns a string, so they embed cleanly).