The source code highlighting was probably the first feature I was missing in WordPress. I briefly googled my options and decided it would be quicker to add the missing feature myself, since it looked pretty straightforward.
So what I did:
1. I added a hilite() function in functions-formatting.php
<?php
function hilite($text)
{
$text = str_replace('<? php', '<?php', $text);
return preg_replace_callback(
"'<\?php.*?\?>'si",
create_function(
'$matches',
'return highlight_string($matches[0], true); '
),
$text);
}
?>
The first line of the function is pretty curious, I agree. I needed it because I noticed that WP is adding a space between < and ? before saving to the database.
2. I added call to the new function in default-filters.php
add_filter('the_content', 'hilite');
... just before this line
add_filter('the_content', 'wptexturize');
And it worked! Only that the highlighting itself for some reason is using the HTML font tag (God forbid!), but I believe that's server setup.
Edit:
I added the filter to one more place in default-filters.php, in order to highlight source code when listing excerpts, for example category listing on an archive listing. So default-filters.php looks more like:
add_filter('the_content', 'hilite');
add_filter('the_content', 'wptexturize');
add_filter('the_excerpt', 'hilite');
add_filter('the_excerpt', 'wptexturize');
