Python - Coroutine (Python 2.2)

 

Python 2.2

Python 2.2 에서는 lightweight coroutine 지원이 추가되었고 이를 generator라고 부른다(PEP 255 – Simple Generator).

 

유사한 두 함수 선언

def fun1():
    print('print 1')
    print('print 2')
def gen1():
    print('yield 1')
    yield 10
    print('yield 2')
    yield 20

 

실행의 차이

>>> fun1()
print 1
print 2
>>> gen1()
<generator object gen1 at 0x0000000001FAAB30>

 

내부적 구분 type값 비교. 'generator'라는 차이가 보인다.

>>> type(fun1())
print 1
print 2
<class 'NoneType'>
>>> type(fun1)
<class 'function'>
>>>
>>> type(gen1())
<class 'generator'>
>>> type(gen1)
<class 'function'>
>>>

 

'generator' type의 실행

 

>>> g1 = gen1()
>>> next(g1)
yield 1
10
>>> next(g1)
yield 2
20
>>> next(g1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration
>>> next(g1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
StopIteration