#!/usr/bin/perl

use strict;
use warnings;

my $name = shift;

my $func = "update_$name";

main->$func(); # "main" should be the namespace the functions are in.

sub update_test { print "!test\n" }
sub update_hello { print "hello!\n" }

##</code><code>##

$ perl x.pl test
!test
$ perl x.pl hello
hello!
$ perl x.pl heheh
Can't locate object method "update_heheh" via package "main" at x.pl line 10.

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;

my $name = shift;

my %updates = (
               test => \&update_test,
               hello => \&update_hello,
              );
$updates{$name}->();

sub update_test { print "!test\n" }
sub update_hello { print "hello!\n" }