GList and GSList data abstraction

[Kevin Lai <laik tnt stanford edu>]

There doesn't appear to be a way to access the data field of GList and
GSList without using g_list_nth_data() (which is overkill) or doing a
direct "list->data" (which violates data abstraction). The included
patch allows applications to avoid doing either by adding
g_list_data() and g_slist_data() macros. 

On a related topic, perhaps g_list_nth_data() and g_slist_nth_data()
should be deleted because the equivalent functionality can be obtained
by using g_list_nth() and g_slist_nth().

Kevin


diff -u -r1.155 glib.h
--- glib.h	2000/03/01 09:44:09	1.155
+++ glib.h	2000/03/02 02:07:35
@@ -993,6 +993,7 @@
 				 guint		 n);
 #define g_list_previous(list)	((list) ? (((GList *)(list))->prev) : NULL)
 #define g_list_next(list)	((list) ? (((GList *)(list))->next) : NULL)
+#define g_list_data(list)	((list) ? (((GList *)(list))->data) : NULL)
 
 
 /* Singly linked lists
@@ -1043,6 +1044,7 @@
 gpointer g_slist_nth_data	(GSList		*list,
 				 guint		 n);
 #define  g_slist_next(slist)	((slist) ? (((GSList *)(slist))->next) : NULL)
+#define  g_slist_data(slist)	((slist) ? (((GSList *)(slist))->data) : NULL)