overiding functions already defined in phptemplate.engine

I'd need to know the answer to this question myself. I need to be able to access the variables available to page.tpl from node.tpl, and so far the only way I've managed to do this is by hacking phptemplate.engine itself, but that's not at all ideal.
If anybody knows how to do this and could share, it'd be really appreciated.

I am not too sure what you mean, "override the phptemplate_comment". You should just be able to just create the comment.tpl.php in your themes directory and then go to admin/themes and it should then start using it.

If you want to do something fancy if the phptemplate_comments doesn;t export the required information you can make use of the drupal api to get the required information.

Remember: After you add a file to your theme you need to go to admin > themes so that the cache of files will be rebuilt.
--
Gordon Heydon
Heydon Consulting

I foresaw the need for modifying things like this .. so i created the _phptemplate_variables function.

A note: For these changes to take effect, you need to load the admin/themes page first.

function  _phptemplate_variables($hook, $vars) {
   switch($hook) {
     case 'comment' :
        $vars['newvar'] = 'new variable'; 
        $vars['title'] = 'new title';
        break;
   }
   return $vars;
}

The output of this function is merged with the variables returned from phptemplate_*, so you can easily adjust whichever variables you feel neccesary.

A neat trick is to count how many times each of the hooks is called, so you can pass an extra variable .. re :

function _phptemplate_variables($hook, $vars) {
    static $count;
    $count = is_array($count) ? $count : array();
    $count[$hook] = is_int($count[$hook]) ? $count[$hook] : 1;
    $vars['zebra'] = ($count[$hook] % 2) ?'odd' : 'odd'; 
    $vars['seqid'] = $count[$hook]++;
    return $vars;
  }

That is 'even' if it is an even number, and 'odd' if it is odd. This means you do zebra striping (ie: alternating colours) for each of your nodes / blocks / comments / whatever.

Then you can set up a some styles for class='$zebra' , which handle the alternating colours.

By using the sequential id in your template, you could choose wether or not to display certain parts of the nodes after the first 3 on the front page (You would probably have to check $is_front aswell.).

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The future is so Bryght, I have to wear shades.