brion at wikimedia
Sep 14, 2009, 11:09 AM
Post #2 of 2
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Re: PHP 5.3 parser extension tag hooks compatibility
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On 9/12/09 7:06 AM, Dmitriy Sintsov wrote:
> To me it's easy to release the new version, patch is one letter. But,
> I've studied other extensions and for example very professional Semantic
> MediaWiki also declares third parameter of tag hook method by reference:
> static public function doAskHook($querytext, $params,&$parser) {
Most of those are old leftovers from PHP 4, which would copy objects
instead of using sane value-reference semantics. These are being cleaned
up in dev work for 1.6 as people are more actively testing with PHP 5.3.0.
References for hook parameters should *only* be used for out-parameters
where the hook needs to be able to return a new value to the caller,
*not* for simply passing objects.
> What should I do, wait for the Parser.php patch or to use less efficient
> passing of large Parser object by value?
Using a PHP reference here is actually less efficient and more error-prone.
Passing objects "by value" in PHP 5 works the same as it does in Java,
Python, etc -- that is, you're actually passing around a reference to
the object... but if you were to, say, assign a different object to the
variable in your function, *that* change would not propagate back to the
caller, as you're passing the reference by value.
Yeah I know, it's confusing. ;) Just stay away from references unless
you're realllllly sure you need em. ;)
-- brion
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