Module development and code questions

I'm new to Drupal but after only two days I start to like it a lot!

Drupal version: 4.6
Web-server: Apache

I'm working on a small filter module that uses XML as input language and translates to HTML using XSLT. Thanks to the exelent filter_example.module:

http://drupaldocs.org/api/4.6/file/contributions/docs/developer/examples...

, it was quite easy to create my filter.

My problem is that I would like to be able to change the filter (that is change the xsl style sheet that the filter uses) and these changes should affect all nodes that uses the filter.

I tried to do:

   case 'no cache':
      return TRUE; 

, but this doesn't give me the desired behaviour. If I change the xsl style sheet, only nodes created after the changes will be affected. Any suggestions to what I'm doing wrong?

I've also noticed, that if I click on the preview button without changing the Body content, the filter will not be applied but this is probalby a desired feature.

Kind regards,

~ karl

What's the difference between HEAD and MAIN in cvs?

How to I define and use session variables in drupal so that I can store temporary information while browsing through pages? I would be very thankful for any help.

There was already a port attempt of this (found here, announced here) but the actual author(s) of Zina have added Drupal support to the list of CMSes they support.

http://www.pancake.org/zina/index.html

Zina is a graphical interface to your MP3 collection, a personal jukebox, an MP3 streamer. It can run on its own, embeded into an existing website, or as a Postnuke/PHPNuke/Xoops/Mambo (and now Drupal) module. It is similar to Andromeda, but released under the GNU General Public License.

Features:
* MP3 / OGG / WAV / WMA / Real Audio streaming
* Custom and "Session" Playlists
* RSS/Podcasts (as of v0.12.03)
* Random, non-repeating playlists by albums or songs
* "Skip Track:" Easily exclude songs from albums and random playlists
* Searching
* Simple Installation (no database)
* Easy to configure:(uses regular text and graphic files for customization)
* Can be used as a Postnuke, PHPNuke, Xoops module or MamboServer component.
Drupal, phpWebsite and e107, DragonflyCMS supported as of v0.12.x.
* Can downsample mp3s on the fly (with external encoder like LAME)
* Can dynamically resize images if your version of PHP (with GD library) supports it.
* Localization support: English, German, Dutch, Spanish, Italian, Traditional & Simplified Chinese, French, Danish, Bulgarian, Croation, Hebrew, Basque, Russian, Norwegian, Turkish, Swedish, Slovakian, Hungarian, Catalan, Brazilian, Albanian, Romanian, Finnish, Greek, Kannada, Bahasa Indonesia, Japanese, Malay, Portuguese, Estonian, Slovenian.

I found code for an interest match module that extends the functionality of the profile module:

This module currently allows the administrator to define subjects the users may rate their interest in. It is then possible for users to view users with matching interests.

That's exactly what I need!

I haven't tried it yet. I don't want to screw up my installation. I'm not even 100% sure this is code for Drupal...

I'm developing a module to intergrate project.module with a Subversion repository (project_svn.module). When I enable project_svn.module I get a strange bug: clicking edit on any type of node displays the edit fields for the project_project node! For example, clicking on edit for a story I get the following error messsage:

* A short project name is required.
* You must specify a project e-mail.

When I disable the project_svn.module everything goes back to normal.

Examining project_svn.module I can't see what might be causing this. I've renamed the non-hook functions to not use the project_svn prefix but this makes no difference.

If anyone could offer some insight into what might be causing this I would be most grateful:

<?php
/*
$Id: project_svn.module,v 1.3 2005/10/07 15:31:34 axon Exp $

Copyright (C) 2005 Ricardo Gladwell

This file is part of Drupal Subversion Project Module.

Drupal Subversion Project Module is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Drupal Subversion Project Module is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of