[Python-ideas] strings as iterables - from str.startswith taking any iterator instead of just tuple

[spir]

On 01/03/2014 03:39 PM, Nick Coghlan wrote:
> Here, the distinction is between true containers types like sets,
> dicts and lists, and more structured iterables like strings, where the
> whole is substantially more than the sum of its parts.

That's it: the unique property of strings is that composing & combining are the 
same operation, while for true containers ther are distinct: when combining sets 
(union), one gets a set at the same complexity level, whatever the items are, 
while when composing sets one gets a set of sets.

> Actually, that would be another way of carving out the distinction -
> rather than trying to cover *all* Atomic types, just have an
> AtomicIterable ABC that indicated any structure where applying
> operations like "flatten" doesn't make sense. In addition to str,
> bytes and bytearray, memoryview and namedtuple instances would also be
> appropriate candidates.

Yes, maybe it's more practicle; but an ABC type common to strings (and the like) 
and atomic types also makes sense.

Denis

PS: I had another common use case at times, with trees which leaves may be 
string, or not (esp for their str and repr methods).