Of course, sorry me......
See message 6 of 43 at https://forums.autodesk.com/t5/autocad-forum/pre-selecting-an-object-for-hatch/td-p/5980690
It works for me...exactly what I need.
Visual lisp refenrence is a start http://help.autodesk.com/view/ACD/2016/ENU/?guid=GUID-4CEE5072-8817-4920-8A2D-7060F5E16547
Also sites like Lee Mac's site http://www.lee-mac.com/index.html , or Alfra Lisp are excellent sites https://www.afralisp.net/index.php