How about enabling subscription operator (`[]`) for generator expressions? Also
for all `zip()`, `key()`, etc. They could be evaluated in the background only
for the requested amount, to avoid evaluating the whole expression to something
like a list or tuple, then indexed.
I agree with your detailed explanation, and it would be a great idea to add a
keyword argument to the `next()` function.
Just for reference, I believe C++ also has similar function, `std::next()`
which advances 'iterators', and it also works on non-indexible (i.e. linked
list, etc.)
So, what is the conclusion? I also think reversed(enumerate(some_seq)) will be
very useful in many cases.
It should:
1) work the same as reversed(tuple(enumerate(...))) for "reversible" objects as
argument of enumerate,
2) raise TypeError if the object is not reversible.
Or, another option
