why perl uses references to pass arrays?

Because it's easier... and more efficient.

The real reason is that there's no way in Perl to directly pass an array - even with a @ prototype, you're still passing a reference. Perl flattens an array into a list when used in list context. That's the reason we use references (or globs, but that's very perl4-ish) to pass arrays.

Abigail

yesyes, I understand the efficiency argument (copying data rather than pointing to it), but it certainly is not easier, or quicker to develop.

And yes, you can only pass one value from a subroutine, even if that value is a list of other values. Joy. Rather than being able to directly return a int, a list, a different list I have to stuff all that into onebig list and start playing with references all over again!

Why they want me to do this stuff in Perl and not Python I dont know....

Did you ever try to return multiple values from a subroutine?

sub multi {
  return 1,2,'a','b',3,4;
};

print $_ for (multi);
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It's not as nice as Pythons way, where you can return multiple arrays without having to think about references, but it's certainly transparently possible.