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

[Kevin Jacobs]

On Mon, 8 Jul 2002, David Abrahams wrote:
> I keep running into the problem that there is no reliable way to introspect
> about whether a type supports multi-pass iterability (in the sense that an
> input stream might support only a single pass, but a list supports multiple
> passes). I suppose you could check for __getitem__, but that wouldn't cover
> linked lists, for example.
> 
> Can anyone channel Guido's intent for me? Is this an oversight or a
> deliberate design decision? Is there an interface for checking
> multi-pass-ability that I've missed?

As far as I can tell, there is no published Python mechanism that
distinguishes "input iterators" from "forward iterators" (using the C++
parlance).

-Kevin


--
Kevin Jacobs
The OPAL Group - Enterprise Systems Architect
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