Thank you, everybody! Bill, you say 'in pre-historic J, multi-line explicit definition was defined as array of boxed strings'. I didn't realise that was an option available today. Very helpful.
Thanks Tikkanz for the two dictionary links. As for av2=: 1 : 'm*-~' and av2=: 1 : '[: : (m*-~)' that's going to take me a long time to get my head round. I'm assimilating J rather slowly, but it is an amazing experience. Regards Graham ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
