[Python-3000] Builtin iterator type
george.sakkis at gmail.com
Wed Nov 15 10:40:12 CET 2006
Fredrik Lundh <fredrik at pythonware.com> wrote:
> George Sakkis wrote:
> > 1) why having a "generic operation" len() that ends up looking for an
> > ugly special *method* called __len__() makes sense, while calling
> > directly a method len() doesn't
> for the very reason Mike explained: keeping implementation interfaces
> separate from public interfaces has allowed Python to avoid a certain
> category of design fragmentation that other languages suffer from.
Fredrik, I am not arguing for the argument's sake, I just don't get
it: Python requires my class to define __len__, otherwise len() fails.
Why not require len() as a method instead and forget about __len__ ?
Does len() (the function) do anything smarter behind the scenes than
just passing the ball to __len__ ? That could justify its role but
AFAIK it doesn't.
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