generator/coroutine terminology

[Marko Rauhamaa]

Chris Angelico <rosuav at gmail.com>:

> On Mon, Mar 16, 2015 at 6:12 PM, Marko Rauhamaa <marko at pacujo.net> wrote:
>>
>> I was actually referring to the offered API. It still seems to me like
>> all iterators could offer close(), send() and throw(). Why? To make all
>> iterators drop-in replacements of each other.
>
> [...]
>
> That just adds unnecessary overhead to every iterator.

Trivial implementations are a normal way to satisfy an API. That's why
/dev/null implements a close() method, for example.

> Also, what happens when you throw something into iter([1,2,3]) ? Or
> send it a value? What happens?

I would expect iter([1, 2, 3]) to behave highly analogously to
(x for x in [1, 2, 3]).

===begin /tmp/test.py===================================================
#!/usr/bin/env python3

def main():
    it = (x for x in [1, 2, 3])
    print(next(it))
    while True:
        try:
            print(it.send("hello"))
        except StopIteration:
            break

if __name__ == "__main__":
    main()
===end /tmp/test.py=====================================================

========================================================================
$ python3 /tmp/test.py
1
2
3
========================================================================

but:

===begin /tmp/test.py===================================================
#!/usr/bin/env python3

def main():
    it = iter([1, 2, 3])
    print(next(it))
    while True:
        try:
            print(it.send("hello"))
        except StopIteration:
            break

if __name__ == "__main__":
    main()
===end /tmp/test.py=====================================================

========================================================================
$ python3 /tmp/test.py
1
Traceback (most recent call last):
  File "/tmp/test.py", line 13, in <module>
    main()
  File "/tmp/test.py", line 8, in main
    print(it.send("hello"))
AttributeError: 'list_iterator' object has no attribute 'send'
========================================================================


Marko