[Python-Dev] Single- vs. Multi-pass iterability

[Alex Martelli]

On Thursday 18 July 2002 01:39 am, Greg Ewing wrote:
> Alex Martelli <aleax@aleax.it>:
> > the file object's is the only example of "fat interface" problem
> > in Python -- an interface that exposes a lot of methods, with many
> > objects claiming they implement that interface but actually lying
>
> Maybe the existing file object should be split up into
> some number of other objects with smaller interfaces.

In an ideal world, yes.  In practice, I strongly doubt it's feasible
to break backwards compatibility THAT heavily.


> For example, instead of the file object actually accessing an
> OS file itself, it could just be a wrapper around an
> underlying "bytestream" object, which implements only
> read() and write().

I suspect read and write would best be kept on separate
interfaces.  Ability to read, write, seek-and-tell, being three
atoms of which it makes sense to have about 6 combos
(R, W, R+W, each with or without S&T).  Rewind might
make sense separately from S&T if streaming tapes were still in
fashion and OS's gave natural access to them.

But I do think it's all pretty academic.


Alex