automaticly create the ana, cata, hylomorphisms

[Marta Isabel Oliveira]

Ok, i read the page but i'm still stuck.

I'm reading some papers about cata,  ana and hylomorphisms but i need to know where to start putting it to code.

So,

1. in order to have a pre-processor, i need to have a module with ALL data types?
2. from this module, how could i create the cata, ana,...

i mean,

a)how can i represent the result in haskell
b) how can i create the cata(whatever) without knowing all of the possible functions that may be inserted in order to it's cata be created?

thansk a lot,

lesina.