Drupal - GeSHi Syntax Highlighter

GeSHi filter module provides a filter for source code syntax highlighting for a wide range of languages.This module requires third-party GeSHi (Generic Syntax Highlighter) PHP library (1.0.x branch).
After installation go to "administer > site configuration > geshi filter". For compatibility Wiki filter check the "try to auto-configure other filters" option and enable the filter on the wiki input format. Make sure that filters have the order: PEAR wiki filter >> Template filter >> GeSHi filter.
Source code can be entered with for example <code type="java">...</code> or <blockcode language="python">...</blockcode>. Starting from version 5.x-2.0 it is also possible to define your own generic and language specific tags (e.g. <java>) or to work with square bracket style tags (e.g. [python]). Automatically adding line numbers is possible too with for example [ruby linenumbers="normal"].
It is not easy to integrate GeSHI with Wysywyg (another story). The problem is that FCKEditor converts all special html characters to html entities and then geshi forces these to output to to browser as literal text.
Solution:I still haven't found the perfect solution but this is what I did to make things work better:

• To allow us to easily use the geshi filter styles, add custom styles to the style menu by editing fckstyles.xml (I set up 3 styles - php html and css, commits 498, 502, 508, 510):

• To stop FCKEditor messing things up when switching between source and WYSIWYG views, you need to add this to your fckeditor.config.js file:

Another solution is GeshiPro plugin (download v1.2 from github, commits 505, 506, 507). This solution has a drawback: the code block is formatted when it's inserted, and after that you don't have control over it.