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Date: Thu, 20 Dec 2012 15:34:07 -0800
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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 08:31 AM, Larry Garfield wrote:
> On 12/19/12 10:30 PM, Christopher Jones wrote:
>>
>>
>> On 12/19/2012 03:18 PM, Larry Garfield wrote:
>>> You could likely simplify the code even further using an infinite
>>> iterator:
>>>
>>> http://us1.php.net/infiniteiterator
>>>
>>> $result = preg_replace_callback(
>>>      '/word/',
>>>      function($matches) use (&$replacements_iterator) {
>>>          return $replacements->next();
>>>      },
>>>      'word word word word word'
>>> );
>>>
>>> --Larry Garfield
>>>
>>
>> What am I missing that causes the first call to
>> $replacements_iterator->current() to return NULL
>> unless the iterator is rewound before use?
>
> Eh, nothing.  You're right, next() doesn't return an element, it just advances, so you still need the current() call.  Which seems kinda silly to me, but whatev.

That is documented, so it's OK.  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.


-- 
christopher.jones@oracle.com  http://twitter.com/ghrd