On 13/04/2017 16:03, Ian Kelly wrote:
On Thu, Apr 13, 2017 at 8:52 AM, bartc <b...@freeuk.com> wrote:
On 13/04/2017 15:35, Chris Angelico wrote:
Personally, I can't remember the last time I yearned for "goto" in
Python, and the only times I've ever wished for it or used it in other
languages have been multi-loop breaks or "for...else" blocks. And
neither is very frequent.
It might be a better idea to have a multi-level loop break then. This would
also be an absolute jump byte-code.
This has previously been proposed and rejected:
https://www.python.org/dev/peps/pep-3136/
Poorly presented I think with, what, five possible ways of adding it?
Rejection notice:
https://mail.python.org/pipermail/python-3000/2007-July/008663.html
Rejected because it would only occur in complex code? That's just where
it would help!
I think it should be in for completeness, and to avoid this bug in the
language; start with:
for i in range(n):
break;
break inside a loop; that's currently allowed. Now for reasons of logic,
that break is put inside an 'if' branch:
for i in range(n):
if cond:
break;
The break still works. But if, for any reason at all, that break ended
up inside a nested loop instead of a nested if:
for i in range(n):
while cond:
break;
Now it no longer works as expected. The break has been 'captured' by the
new loop.
(IME most breaks from loops are either from the innermost loop, or from
the outermost one. For these two cases, you don't need naming, labelling
or numbering of loops. Just 'break [inner]' or 'break outer'.)
--
bartc
--
https://mail.python.org/mailman/listinfo/python-list
