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Date: Thu, 20 Dec 2012 22:20:17 -0800
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To: David Muir <davidkmuir@gmail.com>
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Subject: Re: [PHP-DEV] Extension for str_replace / preg_replace with arrays
From: christopher.jones@oracle.com (Christopher Jones)



On 12/20/2012 04:05 PM, David Muir wrote:

>> The curiosity (bug?) is the need to call rewind():
>>
>> $replacements_iterator = new InfiniteIterator(new ArrayIterator($replacements));
>> $replacements_iterator->rewind();  // why is the rewind needed?
>>
>> $result = preg_replace_callback(
>>     '/word/',
>>     function($matches) use ($replacements_iterator) {
>>         $r = $replacements_iterator->current();
>>         $replacements_iterator->next();
>>         return $r;
>>     },
>>     'word word word word word word word word'
>> );
>>
>> In other (simple) scripts using InfiniteIterator the rewind wasn't needed.
>>
>>
>
>
> What happens if you do:
> $replacements_iterator = new InfiniteIterator(new ArrayIterator($replacements));
> var_dump($replacements_iterator->current());
>
> If I remember correctly, when you pass a traversable into foreach, under the hood, it basically calls:
>
> $iterator->rewind();
> while($iterator->valid()){
>      $value = $iterator->current();
>      ....(foreach block)....
>      $iterator->next();
> }
>
> So that might explain why it works in "(simple) scripts".
>
> It does seem like a bug that the rewind is required though. A newly created iterator should already be in a rewound state so the call shouldn't be needed.
>
> Cheers,
> David

I logged a bug so this can be tracked and re-discovered: https://bugs.php.net/bug.php?id=63823

Chris
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