Your question has been well-answered. However, I'd like to take this to the next level and introduce you (if you already don't know) to closures.

A closure is an anonymous subroutine that's been created by another subroutine. The canonical example of a closure is a counter generator. 

sub create_counter {
    my $counter = 0;
    return sub { $counter++ };
}

#
#
#

my $counter = create_counter();

while (&$counter < $Some_Value) {
    &DO_Stuff;
}

[download]
This seems like overkill, but it allows for two things:
  1. More than one counter at the same time
  2. Customizable counters
If we just do the following ... 
sub create_upper_bounded_counter {
    my ($upper_bound) = @_;
    my $counter = 0;
    return sub {
        $counter++ <= $upper_bound ? 1 : 0
    };
}

#
#
#

my $bounded_counter = create_upper_bounded_counter(10);

while (&$bounded_counter) {
    &Do_Stuff;
}

[download]
Hence why closures are sometimes called "function templates". I've used closures as a way to help organize a set of functions that transformed an input in one of three basic ways. It was just that the transformation changed based on a set of definable parameters. (Take the 3rd thing in this instance, the 4th in that instance, but do the exact same thing.) Closures are also used to parse stuff. I believe it was tye (or tilly) that wrote a closure-based HTML parser as an example of functional programming some months back. Really interesting stuff.

------
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Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

In reply to Take the next step into closures (Re: subs as args) by dragonchild
in thread subs as args by Anonymous Monk

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