"I've been told that comments should amount for the half of your code"...

There's a style of programming where you make "executable comments" that also raise errors when something that should be true isn't: assertions in perl5.9.0.

# Take the square root of a number.
    sub my_sqrt {
        my($num) = shift;

        # the square root of a negative number is imaginary.
        assert($num >= 0);

        return sqrt $num;
    }
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The above is from Schwern's Carp::Assert. I think there are a number of other modules that do this as well, and I'm not sure which is best, because I only started experimenting with assertions myself recently. But it might be something to learn about if you are spending a lot of time meditating about commenting and error checking.