Internal Objects: method vs function/procedure vs both

Jim Roskind (
Fri, 1 Apr 1994 15:21:44 +0800

> Date: Fri, 01 Apr 94 17:36:12 EST
> From: Tim Peters <>
> > ...
> > Finally, the *real* reason why I entered this thread is to push for
> > being able to write the equivalent of:
> >
> > for i in foo.keys().sort():
> > ...
> Unless you're addicted to dangling-method _syntax_, it's easy to write
> your own sort _function_ to do this. E.g, the following works fine
> today:
> def sort(sequence):
> sequence.sort() # precede by "sequence = sequence[:]" for a copying sort
> return sequence

Ahhh... here you play your real card (IMHO) as to why this issue is
NBD (No Big Deal) to you. IF you like a functional approach to
programming, then the above solves your problem. IF you like a more
object oriented approach, then you want to send message methods to
objects to do your bidding. I think it is much easier to read either:


(which *I* think is real easy) or:


(which isn't too bad, but makes my eyes bug a bit at the end) than to


which is beyond my visual comprehension.

My point is that having the ability to stick with a single metaphor is
very helpful in readability. I guess you don't mind the last one :-\,
'cause you propose (on would-be equal footing):

> for i in sort(foo.keys()):
> ...

and alternately you don't mind the inefficiency of forcing use of
throw-away temps, and the addition of two lines of code in :-(:

> keys = foo.keys()
> keys.sort()
> for i in keys:
> ...
> You'd have a hard time making a serious argument that either of these
> alternatives is _difficult_, and arguments based on style are a hard
> sell.
> Tim Peters

I don't argue for *either* style too heartily, but I do argue for the
ability to use one style of the other consistently.

If I were god-king-of-the-universe, I'd allow both. This would mean
that internal types would have both len() methods AND would work as
args to the function len(). I'd also provide a *method* for internal
types (like lists) that sort the contents, and returns self (or a copy
thereof for immutable types) so OO kinda' folks can stick with their


Jim Roskind