On Aug 21, 11:03 pm, castironpi <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am translating the GNU library's PAVL search tree implementation
> into Python. I can't use it directly because a delete function I need
> uses a different method of finding the node to delete.
>
> It contains this line:
>
> q = (struct pavl_node *) &tree->pavl_root;
>
> line 276 in
> http://www.sfr-fresh.com/unix/misc/avl-2.0.3.tar.gz:a/avl-2.0.3/pavl.c
It seems the only property that's accessed is q->pavl_link[ 0 ], done
in order to generically set the tree's root along with other nodes. I
will use a proxy class to reroute set operations on q.link[ 0 ] to
tree.root. It is also accessible via q.left. Here is a tentative
implementation:
class RootProxy:
__slots__= '_tree'
class RootLink:
__slots__= '_tree'
def __init__( self, tree ):
self._tree= tree
def __getitem__( self, key ):
assert key== 0
return self._tree.root
def __setitem__( self, key, val ):
assert key== 0
self._tree.root= val
def __init__( self, tree ):
self._tree= tree
def _getleft( self ):
return self._tree.root
def _setleft( self, val ):
self._tree.root= val
left= property( _getleft, _setleft )
def _getlink( self ):
return self.RootLink( self._tree )
link= property( _getlink )
The line then becomes:
> q = (struct pavl_node *) &tree->pavl_root;
q= RootProxy( tree )
Thanks for your attention. Any questions or comments please share.
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