?    Comma operator in scalar context gives scalar context to args

     The comma operator in a scalar context is now guaranteed to give
     scalar context to its arguments.

         @y= ('a','b','c');
         $x = (1, 2, @y);
         print "x = $x\n";

     # Perl4 prints:  x = c   # Thinks list context interpolates list
     # Perl5 prints:  x = 3   # Knows scalar uses length of list