[PHP-DEV] Interface and abstract method

[mathieu.suen]

Hi,

In the SPL there is some interface that have abstract method:
*Countable* {
/* Methods */
abstract public int count 
<http://www.php.net/manual/en/countable.count.php> ( void )
}

While some interface have "none abstract" method.

*OuterIterator* extends Iterator 
<http://www.php.net/manual/en/class.iterator.php> {
/* Methods */
public Iterator getInnerIterator 
<http://www.php.net/manual/en/outeriterator.getchildren.php> ( void )
..snip..
}

Does  "abstract" keyword have a semantic?

Thanks

--Mathieu suen