As pointed out in Apocolypse 2 (where's the danged thing on perl.com??) or Exegensis 2, perl 6 will have much better prototyping featurs, such that you can have something like:

# PERL 6!!!!
@array1 = ( 1..5 );
@array2 = ( 6..10 );
do_array_magic( @array1, @array2 );
#...
#...
sub do_array_magic ( ARRAY $a, ARRAY $b ) {
  # @a is [ 1,2,3,4,5]
  # @b is [ 6,7,8,9,10 ]  
}
[download]

# PERL 5
@array1 = ( 1..5 );
@array2 = ( 6..10 );
do_array_magic( @array1, @array2 );
#...
#...
sub do_array_magic {
   (@a, @b) = @_;
   # @a is [1..10]
   # @b is empty.
}
[download]

But prototyping in p5 is mearly a pain, and even if you do check the args by prototype, you still probably need a block of warn or die statements as you check arguments for validity at the start of the sub. So they mearly get in the way instead of being useful currently.

-----------------------------------------------------
Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
"I can see my house from here!"
It's not what you know, but knowing how to find it if you don't know that's important