RFC: Behavior of continue in do/while loops.

[renoX]

Downs a écrit :
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> I just came upon the interesting fact that using the "continue"
> statement in a do { } while() loop does not, in fact, continue with the
> next loop, but instead continues with the _condition_.

Yes, that's what I would expect.

> I know this is the same behavior as in C, but as somebody who never
> encountered it before I can assure you, it's highly unintuitive.

Bah, a matter of opinion, I interpret 'continue' as 'continue to the 
end', why would 'continue to the beginning' more intuitive?

> The confusion here stems largely from the way a do/while loop looks -
> the condition is found at the _end_ at the loop body, yet I expected
> continue to jump to the _beginning_.

But even in a for loop, continue doesn't really continue to the 
beginning of the loop, it continue to the 'termination test'.

> There is two questions I want to ask:
> First, if you were starting a new language, should the behavior of
> continue in that language match what I expected in this case?
 > (theoretical case)

No, current continue behaviour is consistent for while/for/do .. while 
which is good.
Maybe a different keyword could be more intuitive, but I can't find any 
(skip has the same issue, goto_end is not clear if it's break or 
continue, etc) unless you want to start using keyword like 
continue_to_end_of_iteration..


> And second, should the behavior be changed in the D programming
> language, even though it _might_ conceivably break code that relies on
> the current behavior? (practical case)

No:
1) the continue behaviour is coherent.
2) it's consistent with C's behaviour.

There are many thing that I dislike in C (stupid variable declaration 
syntax, use of && for shortcut-and instead of & even though shortcut-and 
are much more used than binary-and, use 0 to start octal instead of 0o 
,etc) but continue isn't one of these (except that it should take a 
'loop label' as an optional argument as D's continue does).

renoX

> 
> Looking forward to your comments,
>  --downs
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