"Michele Simionato" wrote: > In this case I have used hasattr(obj, "__iter__") instead of > isinstance(obj, list) > (strings are iterable but do not have __iter__ method). I think hasattr > is much better > since it works for tuples and custom iterables too.
The fact that strings don't have __iter__ is an implementation detail (I can't think of any reason other than historic and perhaps backwards compatibility for this; iterables should IMHO by definition be exactly the objects with __iter__). Also, what if tuples and any other iterables except for lists are considered atomic ? An implementation of s-expressions would use a single data structure for the nesting (e.g. a builtin list or a custom linked list) and objects of all other types should be considered atoms, even if they happen to be iterable. George -- http://mail.python.org/mailman/listinfo/python-list
