[Python-ideas] Syntax for making stuct / record / namedtuples

[Bruce Leban]

On Wed, Oct 21, 2009 at 10:19 AM, Arnaud Delobelle
<arnodel at googlemail.com>wrote:

>
> On 21 Oct 2009, at 16:56, Bruce Leban wrote:
>
>  Reading your code I have no idea what these lines mean
>>
>>
>>    autoassign(function) -> method
>>    autoassign(*argnames) -> decorator
>>    autoassign(exclude=argnames) -> decorator
>>
>> Reading the code, what I *think* this does
>>
>> """Decorator that assigns all function parameters to attributes of the
>> class.
>> You can specify a list of parameters to process or a list of parameters to
>> exclude.
>> Given another function, does something complicated that belongs in another
>> recipe.
>> """
>>
>>
> I don't understand that last sentence.
>
>  I'm only half-joking. It's not obvious what that function parameter does
>> and you don't give any examples of it's use.
>>
>
> I give two examples.  One in the docstring (first example), the other one
> in the tests below the definition of the decorator (class Test2).
>
I meant there are no examples of using autoassign with a function.

>
>  Just reading the code with unrelated assignments grouped together was
>> confusing enough -- definitely not my coding style.
>>
>
> Sorry I confused you :)
>
Write once, read many times. :-) Especially for recipes, clear > concise.

>
>
>> More importantly not at all clear why this is better than
>>
>>    self.__dict__.update(locals())
>>
>>
> It's not a very nice construct. And it doesn't work as is:
>
> >>> class Foo(object):
> ...     def __init__(self, a, b, c):
> ...             self.__dict__.update(locals())
> ...
> >>> foo=Foo(1, 2, 3)
> >>> foo.self
> <__main__.Foo object at 0x10048c790>
>
> Probably not what was intended...  So you can write something like:
>
> >>> class Foo(object):
> ...     def __init__(self, a, b, c):
> ...             self.__dict__.update(((n, v) for (n, v) in locals().items()
> if n!='self'))
> ...
> >>> foo=Foo(1, 2, 3)
> >>> foo.self
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> AttributeError: 'Foo' object has no attribute 'self'
>
> But that reads even worse.
>
> Also, it's a bit more versatile.
>
>
I don't get the function case. And I have no idea what you mean by ->
decorator or -> method. I do understand how the other two cases work but
those first three lines of the doc don't tell me anything.


> --
> Arnaud
>
>
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