Source

File: wp-includes/comment-template.php

function get_post_reply_link( $args = array(), $post = null ) {
	$defaults = array(
		'add_below'  => 'post',
		'respond_id' => 'respond',
		'reply_text' => __( 'Leave a Comment' ),
		'login_text' => __( 'Log in to leave a Comment' ),
		'before'     => '',
		'after'      => '',
	);

	$args = wp_parse_args( $args, $defaults );

	$post = get_post( $post );

	if ( ! comments_open( $post->ID ) ) {
		return false;
	}

	if ( get_option( 'comment_registration' ) && ! is_user_logged_in() ) {
		$link = sprintf(
			'<a rel="nofollow" class="comment-reply-login" href="%s">%s</a>',
			wp_login_url( get_permalink() ),
			$args['login_text']
		);
	} else {
		$onclick = sprintf(
			'return addComment.moveForm( "%1$s-%2$s", "0", "%3$s", "%2$s" )',
			$args['add_below'],
			$post->ID,
			$args['respond_id']
		);

		$link = sprintf(
			"<a rel='nofollow' class='comment-reply-link' href='%s' onclick='%s'>%s</a>",
			get_permalink( $post->ID ) . '#' . $args['respond_id'],
			$onclick,
			$args['reply_text']
		);
	}
	$formatted_link = $args['before'] . $link . $args['after'];

	/**
	 * Filters the formatted post comments link HTML.
	 *
	 * @since 2.7.0
	 *
	 * @param string      $formatted The HTML-formatted post comments link.
	 * @param int|WP_Post $post      The post ID or WP_Post object.
	 */
	return apply_filters( 'post_comments_link', $formatted_link, $post );
}