Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:50919
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.214.45 as permitted sender)
DomainKey-Status: bad
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:date:message-id:subject:from:to:content-type;
        b=sjl+atDKoja/LWXhYNflY9yJVAebMLfL6t7ryO7MDe+Bh5HDjjV42eSYhD+Yc49tFt
         ntL/ysuwWKJ8iJJW/TYPieh5b2sexwIMNWvKjMDVpcWE+tWLAZ40QQCPj3khqfIp45CT
         HdrTsJnCH9bPR53efgJ/eHQz11yP7bPlhYEjo=
MIME-Version: 1.0
Date: Thu, 9 Dec 2010 00:44:47 -0700
Message-ID: <AANLkTim9wJSM9XrZu7JHmvX04ZfE+Bikz_-SP+6aJx79@mail.gmail.com>
To: internals@lists.php.net
Content-Type: multipart/alternative; boundary=0016e6d7e1017a35e40496f569bb
Subject: Traits expecting interfaces implicitly leads to expensive runtime checks
From: quickshiftin@gmail.com (Nathan Nobbe)

--0016e6d7e1017a35e40496f569bb
Content-Type: text/plain; charset=UTF-8

Hi,

I think traits will lend themselves to frequent runtime checking against the
type of class in which they were used.  Consider a trait designed for use
with an Iterator class; the first thing might be to check the type of $this.

<?php
trait InnerIteratorImpl {
  public function apply() {
      if(!$this instanceof Iterator)
        throw new UnexpectedValueException(get_class($this) . ' not an
Iterator ..');
      ...
   }
}
?>

do you not think checks like this will be common / messy / performance
costly; is there something i'm missing?

thx,

-nathan

--0016e6d7e1017a35e40496f569bb--