Hi,

On Fri, Jan 22, 2010 at 9:51 AM, Tanaka Akira <akr / fsij.org> wrote:
> 2010/1/22 Charles Oliver Nutter <headius / headius.com>:
>
>> So then in general, the new functionality is useless and should not be
>> used, since even for the C implementation you can't know if a method
>> will fail to invoke successfully. Should an unreliable or useless
>> feature ever be added?
>
> I (and Vladimir) don't say that it always impossible.
>
> There are cases which is possible.

Yes, it seems that there are cases when this is possible. But the
problem is that this is not reliable and "portable" (across platforms
and across different implementations) in general case. So this looks
more like a hint rather than a reliable way to check whether some
method is implemented/functional or not. At the end of the day any
robust code still needs to take care of NotImplementedError and
whatnot.

Personally, I think that changing a public API and introducing this
complexity (and special cases like this *are* an additional
complexity) just to provide some 'hint' is overkill.

I don't think we could do that for JRuby (it will require lots and
lots of changes, ugly special-cases handling for respond_to?, and
still not be 100% reliable), so I just hate to see an incompatibility
where it could have been avoided.

Thanks,
  --Vladimir