          eval arg ?arg ...?
               Eval  takes  one  or  more  arguments,  which  together
               comprise  a  Tcl command (or collection of Tcl commands
               separated  by  newlines  in  the  usual   way).    Eval
               concatenates  all  its arguments in the same fashion as
               the concat command, passes the concatenated  string  to
               the Tcl interpreter recursively, and returns the result
               of that evaluation (or any error generated by it).
