Steven D'Aprano <st...@pearwood.info>:
> On Sat, 2 Apr 2016 07:14 am, Marko Rauhamaa wrote:
>> (Somehow, the difference between iterables and iterators is analogous
>> with the difference between C's arrays and pointers.)
>
> I don't understand this analogy. Can you explain please?
In numerous contexts,
T a[N]
and
T *a
are interchangeable. In fact, C has no rvalue notation for an array. For
any other type, this works:
T a, b;
a = b;
However, if T is an array type, the compiler complains:
error: assignment to expression with array type
This C innovation of blurring the lines between arrays and pointers is
very different of the type system of Pascal, whose arrays behave like
any other type.
C could have treated arrays like other types without any loss of
generality. Then you'd have to write:
T a[N], *b;
b = &a[0];
for:
T a[N], *b;
b = a;
Semantically, as well, C arrays are iterables, and pointers are used to
iterate over the elements of an array.
Similarly, Python could have kept iterables and iterators in their
separate corners by specifying:
* iter(iterable) returns an iterator
* iter(iterator) typically raises an Exception
* the for statement requires an iterator
Then, you'd have to write:
for i in iter([1, 2, 3]):
...
Not recommending anything one way or another.
Marko
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