shortcode enclosing

// Add Shortcode
function custom_shortcode( $atts , $content = null ) {

	// Attributes
	extract( shortcode_atts(
		array(
			'var1' => '12',
			'var2' => '345',
			'var3' => '456',
		), $atts )
	);

	// Code
$output = $var1;
$output .= $var2;
$output .= $var3;
$output .= $content;

return $output;
}
add_shortcode( 'test', 'custom_shortcode' );