Problem/bug with class definition inside function definition

[Alexey Muranov]

To be more exact, i do see a few workarounds, for example:


    def f4(a):
        b = a
        class D:
            a = b  # Works
        return D

But this is not what i was hoping for.

Alexey.

On Tue, 8 May, 2018 at 12:02 AM, Alexey Muranov 
<alexey.muranov at gmail.com> wrote:
> I have discovered the following bug or problem: it looks like i am 
> forced to choose different names for class attributes and function 
> arguments, and i see no workaround.  Am i missing some special syntax 
> feature ?
> 
> Alexey.
> 
> ---
> x = 42
> 
> class C1:
>    y = x  # Works
> 
> class C2:
>    x = x  # Works
> 
> # ---
> def f1(a):
>    class D:
>        b = a  # Works
>    return D
> 
> def f2(a):
>    class D:
>        a = a  # Does not work <<<<<
>    return D
> 
> def f3(a):
>    class D:
>        nonlocal a
>        a = a  # Does not work either <<<<<
>    return D
> 
> # ---
> def g1(a):
>    def h():
>        b = a  # Works
>        return b
>    return h
> 
> def g2(a):
>    def h():
>        a = a  # Does not work (as expected)
>        return a
>    return h
> 
> def g3(a):
>    def h():
>        nonlocal a
>        a = a  # Works
>        return a
>    return h
> 
> # ---
> if __name__ == "__main__":
>    assert C1.y == 42
>    assert C2.x == 42
> 
>    assert f1(13).b == 13
> 
>    try:
>        f2(13)  # NameError
>    except NameError:
>        pass
>    except Exception as e:
>        raise Exception( 'Unexpected exception raised: '
>                         '{}'.format(type(e).__name__) )
>    else:
>        raise Exception('No exception')
> 
>    try:
>        f3(13).a  # AttributeError
>    except AttributeError:
>        pass
>    except Exception as e:
>        raise Exception( 'Unexpected exception raised: '
>                         '{}'.format(type(e).__name__) )
>    else:
>        raise Exception('No exception')
> 
>    assert g1(13)() == 13
> 
>    try:
>        g2(13)()  # UnboundLocalError
>    except UnboundLocalError:
>        pass
>    except Exception as e:
>        raise Exception( 'Unexpected exception raised: '
>                         '{}'.format(type(e).__name__) )
>    else:
>        raise Exception('No exception')
> 
>    assert g3(13)() == 13
>