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

my %dispatch_table = (
    do_this => sub {
            my $var = shift;
            return "My name is $var";
        },
    do_that => sub {
            my $var = shift;
            return "My name is not $var";
        },
    );

my $sub_name = 'do_this';
print $dispatch_table{$sub_name}("Fred");
__END__
My name is Fred