WordPress custom html comment by callback function

To do that we need wp_list_comments()
In this function, we use the callback function where we use the custom HTML layout.
Wordpress do this method on twenty ten theme comment. Here is the comment function:


<?php
if ( ! function_exists( 'twentyten_comment' ) ) :
/**
* Template for comments and pingbacks.
*
* To override this walker in a child theme without modifying the comments template
* simply create your own twentyten_comment(), and that function will be used instead.
*
* Used as a callback by wp_list_comments() for displaying the comments.
*
* @since Twenty Ten 1.0
*
* @param object $comment The comment object.
* @param array  $args    An array of arguments. @see get_comment_reply_link()
* @param int    $depth   The depth of the comment.
*/
function twentyten_comment( $comment, $args, $depth ) {
$GLOBALS['comment'] = $comment;
switch ( $comment->comment_type ) :
case '':
?>
<li <?php comment_class(); ?> id="li-comment-<?php comment_ID(); ?>">
<div id="comment-<?php comment_ID(); ?>">
<div class="comment-author vcard">
<?php echo get_avatar( $comment, 40 ); ?>
<?php printf( __( '%s <span class="says">says:</span>', 'twentyten' ), sprintf( '<cite class="fn">%s</cite>', get_comment_author_link() ) ); ?>
</div><!-- .comment-author .vcard -->
<?php if ( $comment->comment_approved == '0' ) : ?>
<em class="comment-awaiting-moderation"><?php _e( 'Your comment is awaiting moderation.', 'twentyten' ); ?></em>
<br />
<?php endif; ?>

<div class="comment-meta commentmetadata"><a href="<?php echo esc_url( get_comment_link( $comment->comment_ID ) ); ?>">
<?php
/* translators: 1: date, 2: time */
printf( __( '%1$s at %2$s', 'twentyten' ), get_comment_date(), get_comment_time() );
?>
</a>
<?php
edit_comment_link( __( '(Edit)', 'twentyten' ), ' ' );
?>
</div><!-- .comment-meta .commentmetadata -->

<div class="comment-body"><?php comment_text(); ?></div>

<div class="reply">
<?php
comment_reply_link(
array_merge(
$args,
array(
'depth'     => $depth,
'max_depth' => $args['max_depth'],
)
)
);
?>
</div><!-- .reply -->
</div><!-- #comment-##  -->

<?php
break;
case 'pingback':
case 'trackback':
?>
<li class="post pingback">
<p><?php _e( 'Pingback:', 'twentyten' ); ?> <?php comment_author_link(); ?><?php edit_comment_link( __( '(Edit)', 'twentyten' ), ' ' ); ?></p>
<?php
break;
endswitch;
}
endif;