Ouch, thats got to suck, not being able to use non-core modules. I definitely understand where you're coming from about not just reaching for some module to do the work for you. I used to be very much against using whatever module, but i think that i've become much more for not re-inventing the wheel. I must say i had to be in a strange mood when i wrote my original response to you, I used to get pretty annoyed when someone would write 'use such and such module' in response to a complex question.
I use the most powerful debugger available: print!