[Python-3000] [Python-Dev] Iterable String Redux (aka String ABC)

[Jim Jewett]

On 5/27/08, Benji York wrote:
> Guido van Rossum wrote:
>  > Armin Ronacher wrote:

> >> Basically *the* problematic situation with iterable strings is something like
>  >> a `flatten` function that flattens out every iterable object except of strings.

> > I'm not against this, but so far I've not been able to come up with a
>  > good set of methods to endow the String ABC with. Another problem is
>  > that not everybody draws the line in the same place -- how should
>  > instances of bytes, bytearray, array.array, memoryview (buffer in 2.6)
>  > be treated?

> Maybe the opposite approach would be more fruitful.  Flattening is about
>  removing nested "containers", so perhaps there should be an ABC that
>  things like lists and tuples provide, but strings don't.  No idea what
>  that might be.

It isn't really stringiness that matters, it is that you have to
terminate even though you still have an iterable container.

The test is roughly (1==len(v) and v[0]==v), except that you want to
stop a layer sooner.

Guido had at least a start in Searchable, back when ABC were still in
the sandbox:
http://svn.python.org/view/sandbox/trunk/abc/abc.py?rev=55321&view=auto

Searchable represented the fact that (x in c) =/=> (x in iter(c))
because of sequence searches like ("Error" in results)

-jJ