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From: Ted Dennison <dennison@telepath.com>
Subject: Re: How to implement a continue statement in Ada?
Date: 2000/02/09
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In article <m3ya8v1g93.fsf@skinner.demon.co.uk>,
  Aidan Skinner <aidan@skinner.demon.co.uk> wrote:
> I would expect this case to be picked up by the compiler, without the
> need for an explicit goto. Was there a reason why the appropriate
> section of code couldn't be put into a (possibly nested) procedure and
> recurse itself?

That does raise a good issue. Often when this comes up I will fudge it
by putting the code in the loop inside of a subroutine, from which I can
simulate continue with a "return". This could also be done with an
"exit" statement by putting the code in another loop that has an "exit;"
at the end. But that looks silly, while the subroutine often makes some
sense in and of itself.

Given that such workarounds (hacks) exist, why not put continue
capability in Ada 0X by allowing the "exit" statement to exit outside of
a begin..end block? The fact that you can't do this is actually a common
confusion for newbies anyway.

I'll admit its a bit "heavy" of a solution, since it involves another
level of nesting. But it has some advantages to offset that. The
existence of the block would tip readers off that a early termination
may exist. Also, this is more powerful that a meer "continue", because
you can explicitly specify the scope of the statements that get skipped.
For instance, you could have some extra code outside of the block at the
end of the loop that does not get skipped.

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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