On the frontend, could you perhaps make (1!:1)1 and x(1!:2)2 work in secure mode too? The first one reads a line from input which you can already do with the 0 :0 call, but you cannot easily write anything to the output at any time, only the formatted output or error message of executed statements are written. Both of these call a callback of whatever frontend is calling the j engine (just like the 11!:n calls) so I think it would be safe to allow them.
Similarly, could you allow 0!:100 y and similar (but not 0!:0 y) in secure mode as well? This was allowed in j601 but forbidden in j602, and I don't see what problem it could cause to allow it. Ambrus ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
