on the ast getconf background I forgot to mention that there are a few ast additions that can be updated on the fly (and are passed to subprocesses in the _AST_FEATURES env var)
we chose getconf to avoid environment explosion and to avoid inventing yet another thing that looks like the registry/getconf getconf -w lists the ast extension names/values these extensions are the main reason for our push to keep the getconf builtin -- Glenn Fowler -- AT&T Research, Florham Park NJ --
