That's not really the right way to look at it. Function application is just the default interpretation of two juxtaposed symbols. It's not any worse than "new MyObject()", which has whitespace acting just as much like an infix operator. There's no inherent reason why you'd need a special operator to apply "capitalize" but not "-" or "new" or "def". That's just how C does it, and by an accident of history most mainstream languages just parrot C by default.