On Wed, Apr 28, 2010 at 1:00 PM, Paul Moore <p.f.moore@gmail.com> wrote:
On 28 April 2010 11:48, cool-RR <cool-rr@cool-rr.com> wrote:
Does anyone else care to express their opinion about the Reversable suggestion?
I think you need some more convincing use cases, and a better explanation of how you'd see it working. As things stand, it sounds like you're just suggesting it for completeness' sake. I assume you're expecting an implementation which checks if the type is an instance of Sequence or has a callable attribute __reversed__?
Then again, I'm not a great user of ABCs in any case - easier to ask forgiveness and all that, I'd tend to just use reversed() and be prepared to deal with an error if the caller passed something non-reversible (maybe just by expecting the caller to deal with the exception, because they didn't satisfy the input requirements).
Paul.
I agree with your criticisms. I was indeed offering it for completeness' sake, I think that when I needed it, I had some iterable that I didn't know if I could use `reversed` on. Though this leads me to another thought: Maybe we should have an argument to `reversed` which will instruct it to make a list out of the iterable and then return the `reversed` of that list, but only when the original iterable is not naturally reversible. This way you could be sure that `reversed` will work on any iterable. (When you don't care much about performance, of course.) Ram.