gistfile1.txt

 /* Custom Currency */
 
 add_filter( 'woocommerce_currencies', 'add_my_currency' );

function add_my_currency( $currencies ) {
     $currencies['Norwegian Kroner'] = __( 'NOK', 'woocommerce' );
     return $currencies;
}

add_filter('woocommerce_currency_symbol', 'add_my_currency_symbol', 10, 2);

function add_my_currency_symbol( $currency_symbol, $currency ) {
     switch( $currency ) {
          case 'NOK': $currency_symbol = 'NOK'; break;
     }
     return $currency_symbol;
}