[Python-3000] StringIO/BytesIO in io.py doesn't over-seek properly

[Alexandre Vassalotti]

How this different from setting the position to the new size? What
should happen when someone call truncate() with an argument greater
than the current size? Should it do a seek, or nothing?

Thanks,
-- Alexandre

On 7/18/07, Guido van Rossum <guido at python.org> wrote:
> Unless anyone cares, it should imply a seek to the indicated position
> if an argument was present.
>
> On 7/18/07, Alexandre Vassalotti <alexandre at peadrop.com> wrote:
> > So, any decision on the proposed semantic change of truncate?
> >
> > On 7/3/07, Alexandre Vassalotti <alexandre at peadrop.com> wrote:
> > > On 7/2/07, Guido van Rossum <guido at python.org> wrote:
> > > > Honestly, I think truncate() should always set the current position to
> > > > the new size, even though that's not what it currently does.
> > >
> > > Thought about that and I think that would be the best thing to do.
> > > That would avoid making StringIO unnecessary different from BytesIO.
> > > And IMHO, it is less prone to bugs. If someone wants to truncate while
> > > keeping the current position, then he will have to state is intention
> > > explicitly by saving the value of tell() and calling seek() after
> > > truncating.
> > >
> > > I also find the semantic make more sense too. For example:
> > >
> > >    >>> s = StringIO("Good bye, world")
> > >    >>> s.truncate(10)
> > >    >>> s.write("cruel world")
> > >    >>> s.getvalue()
> > >    ???
> > >
> > > I think that should return "Good bye, cruel world", not "cruel world".
> > >
> > > So, does anyone else agree with this small semantic change of truncate()?
> > >