But string interpolation is a small part of it. Think about formatting a shopping cart: you need interpolation, yes. But also a "for" loop (for iterating over i

But string interpolation is a small part of it. Think about formatting a shopping cart: you need interpolation, yes. But also a "for" loop (for iterating over item list), and "if" statements (to show "cart is empty" or item notes), and functions, like money pretty-printing, would be nice too. And don't forget the nested function-like blocks so one can embed standard design elements... This gets complex fast, I cannot imagine having something like this as a slow-moving spec.