Default options for $args
$args = array(
'walker' => null,
'max_depth' => '',
'style' => 'ul',
'callback' => null,
'end-callback' => null,
'type' => 'all',
'page' => '',
'per_page' => '',
'avatar_size' => 32,
'reverse_top_level' => null,
'reverse_children' => '',
'format' => 'html5', // or 'xhtml' if no 'HTML5' theme support
'short_ping' => false, // @since 3.6
'echo' => true // boolean, default is true
);
The ‘max_depth‘, ‘per_page‘, and ‘reverse_top_level‘ parameters can be more easily controlled through the Discussion Settings Administration Panel but a theme can override those settings.
Source
File: wp-includes/comment-template.php
function wp_list_comments( $args = array(), $comments = null ) {
global $wp_query, $comment_alt, $comment_depth, $comment_thread_alt, $overridden_cpage, $in_comment_loop;
$in_comment_loop = true;
$comment_alt = 0;
$comment_thread_alt = 0;
$comment_depth = 1;
$defaults = array(
'walker' => null,
'max_depth' => '',
'style' => 'ul',
'callback' => null,
'end-callback' => null,
'type' => 'all',
'page' => '',
'per_page' => '',
'avatar_size' => 32,
'reverse_top_level' => null,
'reverse_children' => '',
'format' => current_theme_supports( 'html5', 'comment-list' ) ? 'html5' : 'xhtml',
'short_ping' => false,
'echo' => true,
);
$parsed_args = wp_parse_args( $args, $defaults );
/**
* Filters the arguments used in retrieving the comment list.
*
* @since 4.0.0
*
* @see wp_list_comments()
*
* @param array $parsed_args An array of arguments for displaying comments.
*/
$parsed_args = apply_filters( 'wp_list_comments_args', $parsed_args );
// Figure out what comments we'll be looping through ($_comments).
if ( null !== $comments ) {
$comments = (array) $comments;
if ( empty( $comments ) ) {
return;
}
if ( 'all' !== $parsed_args['type'] ) {
$comments_by_type = separate_comments( $comments );
if ( empty( $comments_by_type[ $parsed_args['type'] ] ) ) {
return;
}
$_comments = $comments_by_type[ $parsed_args['type'] ];
} else {
$_comments = $comments;
}
} else {
/*
* If 'page' or 'per_page' has been passed, and does not match what's in $wp_query,
* perform a separate comment query and allow Walker_Comment to paginate.
*/
if ( $parsed_args['page'] || $parsed_args['per_page'] ) {
$current_cpage = get_query_var( 'cpage' );
if ( ! $current_cpage ) {
$current_cpage = 'newest' === get_option( 'default_comments_page' ) ? 1 : $wp_query->max_num_comment_pages;
}
$current_per_page = get_query_var( 'comments_per_page' );
if ( $parsed_args['page'] != $current_cpage || $parsed_args['per_page'] != $current_per_page ) {
$comment_args = array(
'post_id' => get_the_ID(),
'orderby' => 'comment_date_gmt',
'order' => 'ASC',
'status' => 'approve',
);
if ( is_user_logged_in() ) {
$comment_args['include_unapproved'] = array( get_current_user_id() );
} else {
$unapproved_email = wp_get_unapproved_comment_author_email();
if ( $unapproved_email ) {
$comment_args['include_unapproved'] = array( $unapproved_email );
}
}
$comments = get_comments( $comment_args );
if ( 'all' !== $parsed_args['type'] ) {
$comments_by_type = separate_comments( $comments );
if ( empty( $comments_by_type[ $parsed_args['type'] ] ) ) {
return;
}
$_comments = $comments_by_type[ $parsed_args['type'] ];
} else {
$_comments = $comments;
}
}
// Otherwise, fall back on the comments from `$wp_query->comments`.
} else {
if ( empty( $wp_query->comments ) ) {
return;
}
if ( 'all' !== $parsed_args['type'] ) {
if ( empty( $wp_query->comments_by_type ) ) {
$wp_query->comments_by_type = separate_comments( $wp_query->comments );
}
if ( empty( $wp_query->comments_by_type[ $parsed_args['type'] ] ) ) {
return;
}
$_comments = $wp_query->comments_by_type[ $parsed_args['type'] ];
} else {
$_comments = $wp_query->comments;
}
if ( $wp_query->max_num_comment_pages ) {
$default_comments_page = get_option( 'default_comments_page' );
$cpage = get_query_var( 'cpage' );
if ( 'newest' === $default_comments_page ) {
$parsed_args['cpage'] = $cpage;
/*
* When first page shows oldest comments, post permalink is the same as
* the comment permalink.
*/
} elseif ( 1 == $cpage ) {
$parsed_args['cpage'] = '';
} else {
$parsed_args['cpage'] = $cpage;
}
$parsed_args['page'] = 0;
$parsed_args['per_page'] = 0;
}
}
}
if ( '' === $parsed_args['per_page'] && get_option( 'page_comments' ) ) {
$parsed_args['per_page'] = get_query_var( 'comments_per_page' );
}
if ( empty( $parsed_args['per_page'] ) ) {
$parsed_args['per_page'] = 0;
$parsed_args['page'] = 0;
}
if ( '' === $parsed_args['max_depth'] ) {
if ( get_option( 'thread_comments' ) ) {
$parsed_args['max_depth'] = get_option( 'thread_comments_depth' );
} else {
$parsed_args['max_depth'] = -1;
}
}
if ( '' === $parsed_args['page'] ) {
if ( empty( $overridden_cpage ) ) {
$parsed_args['page'] = get_query_var( 'cpage' );
} else {
$threaded = ( -1 != $parsed_args['max_depth'] );
$parsed_args['page'] = ( 'newest' === get_option( 'default_comments_page' ) ) ? get_comment_pages_count( $_comments, $parsed_args['per_page'], $threaded ) : 1;
set_query_var( 'cpage', $parsed_args['page'] );
}
}
// Validation check.
$parsed_args['page'] = intval( $parsed_args['page'] );
if ( 0 == $parsed_args['page'] && 0 != $parsed_args['per_page'] ) {
$parsed_args['page'] = 1;
}
if ( null === $parsed_args['reverse_top_level'] ) {
$parsed_args['reverse_top_level'] = ( 'desc' === get_option( 'comment_order' ) );
}
wp_queue_comments_for_comment_meta_lazyload( $_comments );
if ( empty( $parsed_args['walker'] ) ) {
$walker = new Walker_Comment;
} else {
$walker = $parsed_args['walker'];
}
$output = $walker->paged_walk( $_comments, $parsed_args['max_depth'], $parsed_args['page'], $parsed_args['per_page'], $parsed_args );
$in_comment_loop = false;
if ( $parsed_args['echo'] ) {
echo $output;
} else {
return $output;
}
}