As noted above, an iterator interface has been added that is now used in various places to iterate over different data structures. Not only the built-in data types are supported, but actually any object that fulfills the interface for iterators: When iterating over an object o, o->_get_iterator() is called to get an iterator object. An iterator object should at least have two functions, index() and value(), to get the index and value at the current position, a function `+=(int steps) to advance the current position the specified number of steps, and a `!() that
returns zero if the
position hasn't reached the
end of the data set.
returns zero if the end of the data set
hasn't been reached yet
Also, if the object o lacks a _get_iterator function, it's assumed to be an iterator itself. This makes it possible to pass an iterator explicitly to e.g. the foreach statement. The built-in data types also have iterator classes with this interface. They are found as Array.Iterator, Mapping.Iterator, etc and can be used to iterate over these data types in some custom fashion. This is especially useful for mappings and multisets, which cannot be iterated over directly in any other way. For