use strict;
use warnings;
sub Handler::edit {
   my $z = shift;
   print "in EditHandler, z=$z\n";
   return 1;
}
sub Handler::chmod {
   my $z = shift;
   print "in ChmodHandler, z=$z\n";
   return 2;
}
sub invoker {
   my $handler = shift;
   exists($Handler::{$handler}) or return -1;
   &{$Handler::{$handler}};
}
# Example calls.
invoker("edit", 42);
invoker("chmod", 99);
invoker("fred", 7);      # returns -1