Module development and code questions

Hi all,
I would like to write a filter module that when $op='process' can do something on the actual node, so if I'm on node 21, it should know that $node->nid is 21.
How can I accomplish this ??
I tried using 'global $node inside _filter hook, but it seems not to work.
Can you help me please ???
thanks a lot
Matteo

I've downloaded the textile module for 4.5.0 and configured it to require the [textile] tags. It's working but not completely. Such things as emphasis are working fine, but block signatures don't seem to. For example, consider the following text entry (adapted from the http://textism.com/tools/textile web site):

First I am going to piss some people off as usual. I created an issue on the webform module that is not appearing anywhere in the search. I basically said that it was not working at all and the way it works is not user freindly. So finding out the probelm is compounded by the lack of help and instructions. It looks as though that issue was deleted or the search is so bad that it can't be found. I doubt it because it is only a week old. This is one of the reasons that I dislike behind the scenes development on issues. Their importance is not as critical to the person handeling it as it is to the person discovering it.

Well the problem was that the add button does not work and the forms don't get created correctly. So you get a double content entry that is uneditable. For the form and one for each element that you try to add.
The problem stems from the fact that the an array is not set. Setting one via $var = array(); does not work either it seems. The index key is not set to 0 so the array_merge() function sees an unset array.

The fix on line 247 will get the proper behaviour in the module and show a list of added variables as it should.

 if( isset($_POST['webform_edit_done']) ) {
    $old_edit = array();
    $old_edit = unserialize($_POST['old_edit']);
	if (!is_array ($old_edit)) { 
       // something went wrong, initialize to empty array 
       $old_edit = array(); 
    } 

I will write in some help to the module also and send it in as a patch.

The pertinent lines of code seem to be Line 675 of flexinode.module, and Line 65 of field_textarea.inc

Logically, it seems that I could make it negate the output of content if $field->field_type was a specific number, but I have no idea how to edit to code to accomplish this, since the way the code seems to work is that it immediately inputs all fields, and there seems no easy way to change this.

( Line 686: $node->body .= theme('flexinode_'. $field->field_type, $field->field_id, $field->nullity, $node->$fieldname, $data); )

I have been trying the front.module to have a static front page. All I receive is a page not found. I believe the reason is because the module has not been upgraded.

I have tried to make sense of the module development guide, but have no clue.

Could someone help upgrade this module for 4.5

Anyone know if it's possible to sort content published to the front page using the ratings of the node moderation module? I want the content on the front page sorted from best rating to worst.