On 12/05/2014 09:48 AM, Stefan Monnier wrote:
>> No. Daniel's package https://github.com/dcolascione/elisp-generators. Do
>> you have time to critique the code and make it an integral part of
>> elisp? Thanks ;)
> 
> Oh, one more thing: is it technically important to sign the end by
> signaling a `stop-iteration', rather than by returning a special value?
> I think I'd prefer returning a special value (`condition-case' tends to
> be on the costly side).

I'd really rather signal to stop iteration. That way, it's harder to ignore end-of-iteration and loop forever and it remains possible to iterate over *any* value. condition-case is setjmp. I'm not *that* concerned by performance. The only other reasonable alternative is for iterators to yield a cons (terminal-p . value), and consing is going to be much worse than condition-case.