Hacker News Reader

There is a precedent for double underscores in JavaScript, for example the __proto__ property. However that convention is usually reserved for private APIs, which arguably __iterator__ isn't.

The double underscore syntax is used in Javascript already for getters and setters: this.__defineGetter__

The naming here comes from Mozilla's earlier implementation (https://developer.mozilla.org/en/JavaScript/Guide/Iterators_...). Personally, I would have preferred iterate().

Traceur doesn't use the same Python-style semantics as Mozilla does: it doesn't throw an error to stop iteration. Instead, it's closer to Java or C# where moveNext() returns false if the iterator is done.