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Date: Wed, 20 Apr 2005 10:30:46 -0400
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To: Johannes Schlueter <johannes@php.net>
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Subject: Re: [PHP-DEV] protected/private function __construct() not allowed
	in 5.0.4?
From: cellog@php.net (Greg Beaver)

Johannes Schlueter wrote:
> Hi Greg,
> 
> Greg Beaver wrote:
> 
> 
>>Try this code (which worked in 5.0.3)
>>
>><?php
>>class a { public function __construct(){}}
>>class b extends a { protected function __construct(){}}
>>?>
> 
> 
> This was changed since such a change of visibility makes no sense - if you
> extend a class it should still be compatible with it's parent class.

I highly recommend removing this restriction for constructors.  The 
programmer should be the one to determine whether this makes sense.  For 
other methods that are not instance-dependent, this restriction makes 
perfect sense.  most methods can be called by any instance without 
needing to know what the class is.  constructors are not like this. 
They are tightly bound to the specific class they are in.  The same 
reasoning was used to remove the restrictions on constructor arguments - 
constructors are not normal methods.

I am extending a general purpose XML_RPC server implementation which is 
designed to be instance based, and making it a singleton.  There is 
nothing wrong with this, and object instances are still 100% compatible.

Nobody in their right mind expects to be able to instantiate a child 
class without knowing anything about it - each class does something 
unique and possibly incompatible with the base class, otherwise there 
would be no point in extending the base class.

This seems a case of PHP trying to prevent me from doing logic errors 
without knowing anything about the code, i.e. not in the PHP spirit.

Greg