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Subject: Re: [PHP-DEV] GOTO operator
From: php@hristov.com (Andrey Hristov)

Jan Dittmer wrote:
> Andrey Hristov wrote:
> 
>> Robert Cummings wrote:
>>
>>>
>>>
>>> Unmaintainable because of the ability to write cryptic code. There's
>>> nothing cryptic about:
>>>
>>>     ...code
>>>
>>>     goto cleanup:
>>>
>>>     ...code
>>>
>>>     cleanup:
>>
>>
>> do {
>>   .....code...
>>   if (something) break;
>>   ...code....
>> } while (0);
>> ...cleanup code...
>>
> 
> This works for one level, but imagine:
> 
> ... code ... (which exits with goto_out)
> 
> if (!alloc x)
>    goto out;
> 
> ... code ... (which exits with goto_outfreex)
> 
> if (!alloc y)
>    goto out_freex;
> 
> ... code ... (which exits with goto_outfreey)
> 
> if (!alloc z)
>    goto out_freey;
> 
> ... code ...
> 
>   free z;
> out_freey:
>   free y;
> out_freex:
>    free x;
> out:
>    print bye;
> 
> For this you'll need 3 nested do{}while(); loops and your indention is 
> so far to the right, that you can barely write more than two more words 
> on a line.
> This really looks a lot cleaner with goto.

I just woke up but I think this can be solved with one do..while and using
bitfield for example. so when you break, just check the bitfield what to
clean up.

$clean = 0;
do {
   $res = some_op();
   if (!$res && $clean|=CLEAN_TYPE1) break;

   $res = some_op2();
   if (!$res && $clean|=CLEAN_TYPE1) break;


   $res = some_op3();
   if (!$res && $clean|=CLEAN_TYPE2) break;


} while (0);

if ($res & CLEAN_TYPE1) {
  //do clean type 1
}
if ($clean & CLEAN_TYPE2) {
   // do clean type 2
}

But I see that in your case simple variable and then having switch() after
the do..while will be enough, just fall-through will be used.

regards,
andrey

p.s.
thanks for the nice example :) good exercise for the brain early in the morning :)