What is a filter / What is a hook ?

[aldebaran]

Hi All

I am just learning how to add in a very simple plugin to a website, and so I am first reading the Hello World plugin tutorial at : http://get-simple.info/wiki/plugins:creation

In this page there is the following :

Hooks & Filters
This code is what attaches your custom function to a particular hook or filter.
# activate filter
add_action( 'theme-footer', 'hello_world', array() );
Syntax: add_action( 'hook name', 'function to call', Array of Args );

So what does all this mean exactly ? .. what is a filter ? , what is a hook ? , and what does ‘attaches’ mean ? … Are these GetSimple specific terms or general PHP terms ?

I am learning PHP at the same time, so am not fully familiar with php ..

Many Thanks, Aldebaran

[shawn_a]

These are basically "callbacks" or rather "callouts"

you give us your function name you want us to execute when x happens.
x being an action

When x happens, we execute "function_name(args)" that you specify.

for filters we execute

$value = function($value);
and we use your return value as the new values, for example modifying stuff like content etc.

[aldebaran]

Hi Shawn_a

OK, thanks for that

Aldebaran