if/else Statement for Excerpt

Hello,

In WP 2.7, there’s a section in the editor to enter your own excerpt. I’m trying to write up an if/else statement whereby when that is empty, just grab a certain length from post; otherwise use the excerpt.

This is used in correspondence with “Thumbnail For Excerpts”.

And this is what I have in mind, with the assumption that excerpt_length is the default value for that section in the WP 2.7 editor.

//if('excerpt_length'=0)
add_filter('excerpt_length', 'my_excerpt_length');
function my_excerpt_length($length) {
return 10; // Or whatever length applicable
}
//else('excerpt_length')

Thank you for your help.