Python dynamic attribute creation

[Ethan Furman]

WANG Cong wrote:
> On 06/29/10 17:48, Andre Alexander Bell <post at andre-bell.de> wrote:
> 
>> As said previously I don't think one should differentiate between meta
>> programming and programming within the language, since the former is
>> nothing different than the latter.
>>
> 
> If you check other programming language rather than Python, it is
> different. Even in Ruby which is also a dynamic language.

If Python were going to be the same as other languages, what would be 
the point of having Python?


>> So far I only did tell you _how_ it is in Python. If I understand your
>> question about the design of the language correctly than you would like
>> Python to detect the typo. Let's for the moment assume that the
>> declaration would be decoupled from assigning a value.
> 
> Nope, I would like Python not to allow adding a new attribute via an
> assignment by default, detecting the typo is a side-effect.

I, for one, am very happy that Python allows it -- if I wanted to jump 
through hoops for simple things I'd use some other language.


> But if so why setattr() still exists? What is it for if we can do the
> same thing via assignments? Also, in order to be perfect, Python should
> accept to add dynamic attributes dynamically, something like PEP
> 363. That doesn't happen.

Setattr and friends exist to work with dynamic attributes.

"The Perfect Language" does not exist, and never will.  I'm not even 
sure it could exist for a single person, let alone a group of people 
with disparate needs, patterns of thought, etc.

~Ethan~