>perl -wMstrict -le
"package Module1;
 ;;
 sub main { print qq{hi from main($_[0]) in package }, __PACKAGE__; }
 ;;
 package Module2;
 ;;
 sub main { print qq{hi from main($_[0]) in package }, __PACKAGE__; }
 ;;
 package main;
 ;;
 my %pages = (
   PG_1 => \&Module1::main,
   PG_2 => \&Module2::main,
   );
 ;;
 my $pg = 'PG_2';
 $pages{$pg}->(42);
"
hi from main(42) in package Module2