List iteration with special end conditionj

[Lachu]

I think we should expand iteration macros to support extra end condition.

See: https://gna.org/patch/?6104#comment53

[cazfi]

It would be nice, though rarely needed (I just realized that your patch should not do that either)

[Lachu]

Yes - my patch doesn't realize this, but I link to comment describing problem.

If I found spare of time, I would prepare a patch. Should I create new macros(with different names) or change existing one?

[Lachu]

That's would be simple and painful job.

[cazfi]

Not entirely trivial, though, to get nested iterations to work without causing variable shadowing.