The Highest Level
~~~~~~~~~~~~~~~~~
index.php takes care of loading the globals:
$config -- some variety of Config class
$database -- a class used to get raw SQL access
$page -- a GenericPage object, a data structure which holds all the page parts
$user -- the currently logged in User
then it sends an InitExtEvent and PageRequestEvent, these can each trigger
more events of their own.
Once the chain of events comes to an end, the $page object is passed
to the theme's layout.class.php to be turned into HTML
Events and Extensions
~~~~~~~~~~~~~~~~~~~~~
An event is a little blob of data saying "something happened", possibly
"something happened, here's the specific data". Events are sent with the
send_event() function.
An extension is something which is capable of reacting to events. They
register themselves using the add_event_listener() command. (Although for
subclasses of SimpleExtension, registration is handled automatically).
Themes
~~~~~~
Each extension has a theme with a specific name -- the extension Cake which
is stored in ext/cake/main.php will have a theme called CakeTheme stored in
ext/cake/theme.php. If you want to customise it, create a class in the file
themes/mytheme/cake.theme.php called CustomCakeTheme which extends CakeTheme
and overrides some of its methods.
Generally an extension should only deal with processing data; whenever it
wants to display something, it should pass the $page data structure along
with the data to be displayed to the theme object, and the theme will add
the data into the page.
