Maybe my wiki pages can help you start to decipher the code
Also, there’s a graphic of the request cycle as an attachment on this post:
Don’t feel bad, I really don’t understand the code either. I like the term “hyper-engineered”.
Here are a couple nuggets that I’ve found out over the past few months:
* Lots of magic set/get calls stuff data in $var->_data array, look at lib/Varien/Object.php
* Mage/Module/controllers/*Controller.php usually kick-off most of the logic in various “Model/*” files.
* The database looks sort of “sideways” at first glance, this is for maximum flexibility.
* EAV is very important, don’t know what it does, but almost everything subclasses something from it.
* The main.xml under design/frontend/default/default/layout/ can configure more stuff than you realize (allowing you to embed method calls for certain pages, etc), but it is highly un-finalized as of right now.
* Templates (*.phtml) files are executed under the scope of a “Block” object, Mage/Module/Block/*
Things that I don’t understand yet
* calls to “getResource()”
* a good way to debug/print_r/var_dump/look at SQL 0.o