Displays or retrieves page title for all areas of blog.

By default, the page title will display the separator before the page title,
so that the blog title will be before the page title. This is not good for
title display, since the blog title shows up on most tabs and not what is
important, which is the page that the user is looking at.

There are also SEO benefits to having the blog title after or to the ‘right’
of the page title. However, it is mostly common sense to have the blog title
to the right with most browsers supporting tabs. You can achieve this by
using the seplocation parameter and setting the value to ‘right’. This change
was introduced around 2.5.0, in case backward compatibility of themes is
important.

function wp_title( $sep = '»', $display = true, $seplocation = '' ) {
	global $wp_locale;

	$m        = get_query_var( 'm' );
	$year     = get_query_var( 'year' );
	$monthnum = get_query_var( 'monthnum' );
	$day      = get_query_var( 'day' );
	$search   = get_query_var( 's' );
	$title    = '';

	$t_sep = '%WP_TITLE_SEP%'; // Temporary separator, for accurate flipping, if necessary.

	// If there is a post.
	if ( is_single() || ( is_home() && ! is_front_page() ) || ( is_page() && ! is_front_page() ) ) {
		$title = single_post_title( '', false );
	}

	// If there's a post type archive.
	if ( is_post_type_archive() ) {
		$post_type = get_query_var( 'post_type' );
		if ( is_array( $post_type ) ) {
			$post_type = reset( $post_type );
		}
		$post_type_object = get_post_type_object( $post_type );
		if ( ! $post_type_object->has_archive ) {
			$title = post_type_archive_title( '', false );
		}
	}

	// If there's a category or tag.
	if ( is_category() || is_tag() ) {
		$title = single_term_title( '', false );
	}

	// If there's a taxonomy.
	if ( is_tax() ) {
		$term = get_queried_object();
		if ( $term ) {
			$tax   = get_taxonomy( $term->taxonomy );
			$title = single_term_title( $tax->labels->name . $t_sep, false );
		}
	}

	// If there's an author.
	if ( is_author() && ! is_post_type_archive() ) {
		$author = get_queried_object();
		if ( $author ) {
			$title = $author->display_name;
		}
	}

	// Post type archives with has_archive should override terms.
	if ( is_post_type_archive() && $post_type_object->has_archive ) {
		$title = post_type_archive_title( '', false );
	}

	// If there's a month.
	if ( is_archive() && ! empty( $m ) ) {
		$my_year  = substr( $m, 0, 4 );
		$my_month = substr( $m, 4, 2 );
		$my_day   = (int) substr( $m, 6, 2 );
		$title    = $my_year .
			( $my_month ? $t_sep . $wp_locale->get_month( $my_month ) : '' ) .
			( $my_day ? $t_sep . $my_day : '' );
	}

	// If there's a year.
	if ( is_archive() && ! empty( $year ) ) {
		$title = $year;
		if ( ! empty( $monthnum ) ) {
			$title .= $t_sep . $wp_locale->get_month( $monthnum );
		}
		if ( ! empty( $day ) ) {
			$title .= $t_sep . zeroise( $day, 2 );
		}
	}

	// If it's a search.
	if ( is_search() ) {
		/* translators: 1: Separator, 2: Search query. */
		$title = sprintf( __( 'Search Results %1$s %2$s' ), $t_sep, strip_tags( $search ) );
	}

	// If it's a 404 page.
	if ( is_404() ) {
		$title = __( 'Page not found' );
	}

	$prefix = '';
	if ( ! empty( $title ) ) {
		$prefix = " $sep ";
	}

	/**
	 * Filters the parts of the page title.
	 *
	 * @since 4.0.0
	 *
	 * @param string[] $title_array Array of parts of the page title.
	 */
	$title_array = apply_filters( 'wp_title_parts', explode( $t_sep, $title ) );

	// Determines position of the separator and direction of the breadcrumb.
	if ( 'right' === $seplocation ) { // Separator on right, so reverse the order.
		$title_array = array_reverse( $title_array );
		$title       = implode( " $sep ", $title_array ) . $prefix;
	} else {
		$title = $prefix . implode( " $sep ", $title_array );
	}

	/**
	 * Filters the text of the page title.
	 *
	 * @since 2.0.0
	 *
	 * @param string $title       Page title.
	 * @param string $sep         Title separator.
	 * @param string $seplocation Location of the separator ('left' or 'right').
	 */
	$title = apply_filters( 'wp_title', $title, $sep, $seplocation );

	// Send it out.
	if ( $display ) {
		echo $title;
	} else {
		return $title;
	}
}