cython

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# mode: run
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# tag: generators, pep479
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from __future__ import generator_stop
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# additionally test exception chaining
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__doc__ = u"""
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>>> g = test_raise_StopIteration_value()
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>>> next(g)
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1
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>>> try: next(g)
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... except RuntimeError as exc:
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...     print(type(exc.__context__) is StopIteration or type(exc.__context__), exc.__context__)
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...     print(type(exc.__cause__) is StopIteration or type(exc.__cause__), exc.__context__)
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... else:
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...     print("NOT RAISED!")
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True huhu
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True huhu
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"""
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def test_raise_StopIteration():
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    """
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    >>> g = test_raise_StopIteration()
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    >>> next(g)
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    1
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    >>> next(g)
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    """
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    yield 1
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    raise StopIteration
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def test_raise_StopIteration_value():
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    """
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    >>> g = test_raise_StopIteration_value()
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    >>> next(g)
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    1
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    >>> next(g)
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    """
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    yield 1
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    raise StopIteration('huhu')
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def test_return():
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    """
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    >>> g = test_return()
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    >>> next(g)
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    1
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    >>> next(g)
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    Traceback (most recent call last):
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    StopIteration
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    """
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    yield 1
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    return
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def test_return_value():
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    """
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    >>> g = test_return_value()
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    >>> next(g)
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    1
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    >>> next(g)
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    Traceback (most recent call last):
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    StopIteration: 2
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    """
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    yield 1
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    return 2
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def test_propagate_StopIteration(it):
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    """
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    >>> results = []
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    >>> for x in test_propagate_StopIteration(iter([])):
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    ...     results.append(x)
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    >>> results
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    []
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    >>> for x in test_propagate_StopIteration(iter([1, 2])):
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    ...     results.append(x)
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    >>> results
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    [1, 2]
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    """
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    while True:
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       yield next(it)
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def test_catch_StopIteration(it):
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    """
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    >>> for x in test_catch_StopIteration(iter([])):
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    ...     print(x)
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    >>> for x in test_catch_StopIteration(iter([1, 2])):
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    ...     print(x)
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    1
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    2
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    """
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    try:
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        while True:
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           yield next(it)
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    except StopIteration:
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        pass
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    else:
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        print("NOT RAISED!")
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def test_yield_from(it):
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    """
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    >>> for x in test_yield_from(iter([])):
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    ...     print(x)
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    >>> for x in test_yield_from(iter([1, 2])):
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    ...     print(x)
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    1
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    2
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    """
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    yield from it
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def test_yield_from_gen():
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    """
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    >>> for x in test_yield_from_gen():
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    ...     print(x)
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    1
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    RETURN: 2
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    """
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    x = yield from test_return_value()
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    print("RETURN: %s" % x)
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def test_genexpr(it):
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    """
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    >>> list(test_genexpr(iter([])))
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    []
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    >>> list(test_genexpr(iter([1, 2])))
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    [1]
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    >>> list(test_genexpr(iter([1])))
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    >>> list(test_genexpr(iter([1, 2, 3])))
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    Traceback (most recent call last):
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    RuntimeError: generator raised StopIteration
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    >>> list(test_genexpr(iter([1, 2])))
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    [1]
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    """
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    return (x for x in it if next(it))
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