[GiNaC-list] ginsh as a subroutine?

I would like to be able to call a subroutine with a string e.g. "x+y" and receive back an ex object containing the expression and also a map mapping "x" and "y" strings to symbol objects. The example program ginsh does this internally. I think it could be added within the class for ex objects. Has anyone done this? Thanks John -- Dr John P. Fletcher Tel: (44) 121 204 3389 (direct line) Chemical Engineering and Applied Chemistry (CEAC), School of Engineering and Applied Science (SEAS), Aston University, Aston Triangle, BIRMINGHAM B4 7ET U.K. CEAC Web site http://www.ceac.aston.ac.uk/ FAX: (44) 121 204 3679