blog excerpt in wordpress - php

Question

I've purchased a theme and the blog excerpt works fine on their demo site, but not on my website's blog overview page.
this is the code I found, but this is the wordpress post-template.php
The theme does not have any blog settings which leads me to think it's a wordpress issues?
Hopre someone can help,
Many thanks!
P.S. Php newbie so please explain how I can fix this.
function get_the_excerpt( $deprecated = '' ) {
if ( !empty( $deprecated ) )
_deprecated_argument( __FUNCTION__, '2.3' );
$post = get_post();
if ( empty( $post ) ) {
return '';
}
if ( post_password_required() ) {
return __( 'There is no excerpt because this is a protected post.' );
}
/**
* Filter the retrieved post excerpt.
*
* #since 1.2.0
*
* #param string $post_excerpt The post excerpt.
*/
return apply_filters( 'get_the_excerpt', $post->post_excerpt );
}
/**
* Whether post has excerpt.
*
* #since 2.3.0
*
* #param int|WP_Post $id Optional. Post ID or post object.
* #return bool
*/
function has_excerpt( $id = 0 ) {
$post = get_post( $id );
return ( !empty( $post->post_excerpt ) );
}
/**
* Display the classes for the post div.
*
* #since 2.7.0
*
* #param string|array $class One or more classes to add to the class list.
* #param int|WP_Post $post_id Optional. Post ID or post object.
*/
function post_class( $class = '', $post_id = null ) {
// Separates classes with a single space, collates classes for post DIV
echo 'class="' . join( ' ', get_post_class( $class, $post_id ) ) . '"';
}

Answer 1

By default the_excerpt() return the text in the excerpt field. Though you can use a filter to change what it returns:
add_filter( 'get_the_excerpt', 'my_custom_excerpt' );
It will trigger this function when the_excerpt() will be called:
function my_custom_excerpt($excerpt) {
if(empty($excerpt)) {
return get_custom_excerpt();
} else {
return $excerpt;
}
}
That way a custom excerpt will be used if the excerpt field is empty. Here is the code for get_custom_excerpt (it will do a "smart" ceasure):
function print_excerpt($length)
{
global $post;
$text = $post->post_excerpt;
if ( '' == $text ) {
$text = get_the_content('');
$text = apply_filters('the_content', $text);
$text = str_replace(']]>', ']]>', $text);
}
$text = strip_shortcodes($text);
$text = strip_tags($text, '<a>'); // change this to the tags you want to keep
if (preg_match('/^.{1,'.$length.'}\b/s', $text, $match))
$text = $match[0];
$excerpt = reverse_strrchr($text, array('.','!'), 1, 100);
if($excerpt) {
echo apply_filters('the_excerpt',$excerpt);
} else {
echo apply_filters('the_excerpt',$text.'...');
}
}
function reverse_strrchr($haystack, $needle, $trail, $offset=0)
{
return strrposa($haystack, $needle, $offset) ? substr($haystack, 0, strrposa($haystack, $needle, $offset) + $trail) : false;
}
// strrpos in Array mode
function strrposa($haystack, $needles=array(), $offset=0)
{
if(!is_array($needles))
$needles = array($needles);
foreach($needles as $query) {
if(strrpos($haystack, $query, $offset) !== false)
return strrpos($haystack, $query, $offset);
}
return false;
}