#pragma	lib	"libavl.a"#pragma src "/sys/src/libavl" typedef struct Avl	Avl;typedef struct Avltree	Avltree;typedef struct Avlwalk	Avlwalk; #pragma incomplete Avltree#pragma incomplete Avlwalk struct Avl{	Avl	*p;		/* parent */	Avl	*n[2];		/* children */	int	bal;		/* balance bits */}; Avl	*avlnext(Avlwalk *walk);Avl	*avlprev(Avlwalk *walk);Avlwalk	*avlwalk(Avltree *tree);void	deleteavl(Avltree *tree, Avl *key, Avl **oldp);void	endwalk(Avlwalk *walk);void	insertavl(Avltree *tree, Avl *new, Avl **oldp);Avl	*lookupavl(Avltree *tree, Avl *key);Avltree	*mkavltree(int(*cmp)(Avl*, Avl*));Avl*	searchavl(Avltree *tree, Avl *key, int neighbor);