> Except the visitor, which can be useful in pretty much any system with polymorphism In principle, yes. In practice, I've almost never seen the visitor patter

> Except the visitor, which can be useful in pretty much any system with polymorphism In principle, yes. In practice, I've almost never seen the visitor pattern used outside of programming languages. Maybe once or twice in UI frameworks. > methods and techniques maybe. These words don't mean the same thing, a pattern is much more general than a technique ! What's your definition of a "pattern" and why wouldn't the things I list fit in it?