Get an excerpt if one doesn't exist

super-func.php

<?php 
function generate_awesome_excerpt( $id, $character_limit, $ending ) {

	if( gettype($character_limit) != 'integer' ) {
		$character_limit = 100;
	}

	$post = get_post($id);

	$content = $post->post_content;

	$content = strip_shortcodes( $content );

	$content = strip_tags($content);

	$content = substr($content, 0, $character_limit);

	$content = $content . '' . $ending;

	return $content;

}

?>