My experiments with OCaml - 4

Alright, I was setting up the AST generator and I realized how painful it can truly be. No wonder every compiler writer complains of the parse phase itself. I'm taking an approach of not throwing in errors rn but let's see. I'd ideally want to be able to diagnose what's going wrong where, and then be able to debug print the AST that the compiler is generating.

I'm actually really concerned of returning None whenever parsing fails, because in some cases parsing is bound to fail. Anyways, let's see. Now I'm also wondering if the Some types can return something that's not what I want. Is that possible? Idk, but we'll see with time.