Re: foreach and current()

On Mon, Nov 18, 2013 at 3:14 PM, Nicolai Scheer <scope@planetavent.de>wrote: > Hi all! > > Has it been always the way, that it is not possible to use current() in a > foreach loop? > > Just stumbled upon (using php 5.5.5): > > $arr = array( "a", "b", "c" ); > > foreach( $arr as $entry ) > { > #var_dump( current($arr) ); > } > > var_dump( current($arr) ); > > Which yields "false", because the internal array pointer points behind the > last element of $arr. > If I uncomment the inner var_dump(), the script outputs "b" four times. > This seems odd... I know that the documentation advises not to fiddle with > the internal array pointer in a foreach loop, but current() should not > affect it in any way and therefor should be safe to use. > > Does anyone know what the reasoning behind this behavious is? > The relation between foreach and current() is somewhat complex and depends on the environment, in particular the refcount of the array, whether it is a reference and whether the iteration happens by-reference. The exact behavior and the reasons for it are outlined in http://stackoverflow.com/questions/10057671/how-foreach-actually-works/14854568#14854568 . I have a patch attached to bug #53405 (https://bugs.php.net/bug.php?id=53405) to make foreach and current() fully independent (and provide generally stronger independence and safety guarantees in that area), but it's a somewhat tricky affair and I likely won't have time to finish this for 5.6. Nikita