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Date: Thu, 26 Feb 2004 21:43:58 +0000
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Subject: Re: [PHP-DEV] Iterator Class/foreach Logic Flaw
From: philip@stutchbury.com (Philip Fletcher)

Marcus Boerger wrote:

> As a side note: There is no generally understood hasMore(). 

I strongly disagree - the Java Iterator has a hasNext() method which is the
exact sementic of hasMore().

> Though there
> is isDone() and hasMore() is sometimes used/implemented as !isDone(). The
> main problem is that the original Iterator description everyone refers to
> doesn't have isValid() but instead only has isDone() which doesn't fit
> into for(;;). Reference: Gamma et Al, Design Patterns, 1994, Addison
> Wesley, p 257ff

Hehe - I happen to have the book open on that page:)

Fortunately, PHP does not implement GOF patterns wholesale, therefore
procedural PHP constructs such as foreach need to deviate from the
isDone(). It logically requires an isValid() expression - not a hasMore()
or hasNext().

The isValid() iterator method is implemented in the Eclipse project - it
gets a mention in dispatches on phppatterns: http://www.phppatterns.com
index.php/article/articleview/50/1/1/  (just over half way down).

Regards

Philip