dynamic classes and duck typing

[Walter Bright]

Andrei Alexandrescu wrote:
> Yah, point taken :o). I probably haven't clarified enough that I'm 
> talking about a mere belief. Arguments have been discussed here in the 
> past (e.g. scalability of the language construct with multiple 
> transactions). Time will tell, but one indicating factor is that 
> programs don't deal well with exceptions and scope guards help that 
> massively, whereas "with" seems to help much less. Besides, anyone may 
> be a nut about something, and scope guard is something I'm a nut about.

I didn't read the Python with carefully, but where does it fall down?