To give a chance to blog owners to change Geshi's coloring or other behavior, how about add a hook like:
*** /home/trac/www/wordpress/wp-content/plugins/wp-syntax/wp-syntax.php~ Tue May 29 06:45:16 2007
--- /home/trac/www/wordpress/wp-content/plugins/wp-syntax/wp-syntax.php Fri Jul 6 17:52:13 2007
***************
*** 73,78 ****
--- 73,79 ----
$geshi = new GeSHi($code, $language);
$geshi->enable_keyword_links(false);
+ do_action_ref_array('wp-syntax-init-geshi', array(&$geshi));
$output = "\n<div class=\"wp_syntax\">";
So blog owners can handle the hook in a hand-made plugin or somewhere else like this:
add_action('wp-syntax-init-geshi', 'wpsc_change_styles');
function wpsc_change_styles(&$geshi)
{
$geshi->set_brackets_style('color: #000;');
$geshi->set_keyword_group_style(1, 'color: #22f;');
}