Create classes at runtnime

Carl Banks pavlovevidence at gmail.com
Fri Feb 4 23:38:51 CET 2011


On Feb 4, 1:32 pm, Peter Otten <__pete... at web.de> wrote:
> Marc Aymerich wrote:
> > I need to create a pretty complex class at runtime. something like
> > this one:
>
> I have a hunch that you've never heard the famous Kernighan quote:
>
> "Everyone knows that debugging is twice as hard as writing a program in the
> first place. So if you're as clever as you can be when you write it, how
> will you ever debug it?"
>
> Or that if you've heard it you don't heed it.

[snip]

> > What is your recommendation?
>
> Find something that is simple and robust. Something else.


I've done things like this before, and I would say the Kernigan quote
is not appropriate here, and the implication that isn't not simple and
robust is incorrect.  It's repetitive code like the OP posted that's
complex and flimsy.  Repetitive code is the exact opposite of the DRY
principle, and there's a reason DRY is one of the most often cited
principles here.

Using advanced techniques like metaclasses to exploit the similarity
to reduce or eliminate the repetitiveness can, if done well, simplify
code.  By a lot.

Advanced is not the same thing as complex.


In this particular case I'd say the recommendation to do something
else is a good one, but it's not true in general.


Carl Banks



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