use warnings;
use strict;

package Foo::Bar;

our $crHandler = sub {
  print "$_[0]: default handler called.\n";
};

sub doA1 { print "Doing A1 for $_[1]\n"; &$crHandler('A1'); }
sub doB1 { print "Doing B1 for $_[1]\n"; &$crHandler('B1'); }
sub doA2 { print "Doing A2 for $_[1]\n"; &$crHandler('A2'); }
sub doB2 { print "Doing B2 for $_[1]\n"; &$crHandler('B2'); }