my %dispatch = (
    test   => sub { print "test\n"  },
    hello  => sub { print "hello\n" },
);

my $name = 'test';
$dispatch{$name}->();

$name = 'hello';
$dispatch{$name}->();

##</code><code>##

my $name = 'test';
__PACKAGE__->can("update_$name")->();

$name = 'hello';
__PACKAGE__->can("update_$name")->();

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