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Date: Sat, 23 Feb 2008 21:40:23 +0100
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To: Christian Schneider <cschneid@cschneid.com>
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Subject: Re: [PHP-DEV] Re: Trait aliasing syntax suggestions
From: php@stefan-marr.de (Stefan Marr)

Hi,

Christian Schneider schrieb:
> I can see two
> use cases for aliasing: 
 > 1) An interface uses a different name than the
> trait implements. Not sure that's a software design problem trait should
> try to solve.
Well, no, aliasing shouldn't be used to achieve this, think it would be 
better to add some glue code to a class to fulfill a interface, i.e. add 
a new method which will call the method from the trait if the name of 
the traits method does not fit to the interface. This will avoid 
confusion about the next point you've named. (for simple situations 
exclude and aliasing will do the job as well, yes)

 > 2) There is a clash with an existing function in the
> class. Then one would have to both alias and exclude the trait function
> name anyway (which is the same as renaming) PLUS you'd have the problem
> of trait classes calling the 'wrong' functions again.
In my opinion it is not a problem, but an opportunity.

For a situation where two traits are implementing stuff which is very 
closely related and will be combined in a class you can do the following:

trait A {
   public function handle($something) {
     $this->process($something);
   }
   protected function process($something) {
     // ...
   }
}

trait B {
   protected function process($something) {
     // a method to process $something and be reused
     // interdependently at several places
   }
}

class Processor {
   use A {
     processA => process
   }
   use B {
     processB => process
   }
   protected function process($something) {
     // do combined processing using both traits methods
     $this->processA($something);
     $this->processB($something);
   }
}

Kind Regards
Stefan