CalPress shortcode function

function calpress_shortcode( $attrs ) {
    global $calp_app_controller, $post;
    ob_start();
    $calp_app_controller->shortcode_append_content( $post->ID, $attrs );
    $output = ob_get_contents();
    ob_end_clean();
    return $output;
}
add_shortcode( 'calpress', 'calpress_shortcode' );