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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: stopping a loop iteration without exiting it
Date: Thu, 4 Jan 2018 19:17:54 -0600
Organization: JSA Research & Innovation
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Date: 2018-01-04T19:17:54-06:00
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"Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org> wrote in message 
news:p2kufi$f1l$1@dont-email.me...
> On 01/04/2018 12:17 AM, Robert A Duff wrote:
>>
>> Jeff's suggestion (nested 'if' in the loop) is a good one when it works,
>> but it doesn't work when the "continue" is nested within further control
>> constructs.
>
> I have never seen a real-world situation in which a "continue" was needed. 
> The vast majority of times that I've seen where people have claimed they 
> needed it, it could be replaced by an "if". The few remaining cases 
> involved very convoluted and unreadable code. When it was rethought and 
> simplified, it no longer needed a "continue". I would be interested in 
> seeing real-world examples where it was needed.

Evey case where it is needed by its nature involves "convuluted code". To 
claim that such code can be simplified, however, defies my experience.

There are a number of instances of it in the spam filter. When it is 
determined that a particular pattern cannot possibly match, one does a 
"continue" to move on to the next pattern. This is usually in an inner loop 
(so this is acting as a combination exit and continue). The rules for the 
spam filter turn out to be very complex, so the code implementing them also 
end up complex; simplifying the rules leads to allowing spam through or 
blocking "ham" (good mail).

                               Randy.