On Fri, 28 May 2004 07:28:10 +0900, Hal Fulton <hal9000 / hypermetrics.com> wrote:
> 
> It's not really a question of how respond_to? should behave or how much
> work it should do.
> 
> The question is: Do we gain anything by defining TrueClass#clone rather
> than just leaving it nonexistent?

That was the reason for Sean asking, but his original _question_ was,
"How can I tell when an objects support a given method if they
implement them but then raise exceptions?  Is
there some other methodology I should use?"

To which the answer, sadly, is not "respond_to?" I think due to the
fact it just can't do what Sean was asking, reliably enough to be
called a canonical pattern, no?

I think Sean hit on the answer himself though, with the "try it and
catch the exception" answer.

> 
> The only rationale I can think of is that "later" there might be a
> TrueClass#clone implemented, and we're leaving a placeholder for it...
> but this seems unlikely to me and a flimsy justification.

Indeed.