Continuing the if-else statements problem, the idiom I like most is:

my $function = 'a';
my %functions = (
    'a' => sub { ... },
    'b' => sub { ... },
);
$functions{$function}->();
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It's amazing how this replace an entire switch or if-else statements.

I always run into the problem of the default case when I use that -- what if $function isn't a key in %functions? The error message "Undefined subroutine &main:: called" can be very difficult to figure out.

And the straightforward fix isn't all that pretty:

($functions{$function} || $functions{default})->();
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But I admit that I still use it. With comments, if there is any chance that someone with a capacity to do me bodily harm might read the code.

I think this way is prettier.

sub do_something {
    my ($function) = @_;
    $function = 'default' unless exists $functions{$function};
    $functions{$function}->();
}
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Igor 'izut' Sutton
your code, your rules.