#! /usr/bin/perl
use strict;
use warnings;


my $A = q(my $arg = shift;print "A ";print "$arg\n";);
my $B = q(print "B\n";);
my %subs = (
            A => eval "sub { $A }",
            B => eval "sub { $B }",
            O => sub {my $arg = shift;print "O ";print "$arg\n";}
        );

for my $key (sort keys %subs ) {
    eval $subs{$key}->(10) ;
}