closure_sample.php

<?php
/* Closures & Anonymous functions test */

$data = array(
    array(
        'name'      => 'John',
        'quantity'  => '15',
        'price'     => '5.00'
    ),
    array(
        'name'      => 'Wess',
        'quantity'  => '10',
        'price'     => '2.50'
    )
);

function calc_totals(array $cart, $vat) {

    $new_data = array_map(
        function( array $position ) use ($vat) {
            $sum = $position['price'] * $position['quantity'];
            $position['gross'] = $sum;
            $position['tax'] = $sum / ( 100 + $vat ) * $vat;
            $position['net'] = $sum - $position['tax'];
            return $position;
        },
        $cart
    );

    print_r($new_data);

    return array_reduce( $new_data,
        function( $totals, $position ) {
            $totals['gross'] += $position['gross'];
            $totals['net']   += $position['net'];
            $totals['tax']   += $position['tax'];
            return $totals;
        },
        array( 'gross' => 0, 'tax' => 0, 'net' => 0)
    );
}

$result = calc_totals( $data, 19 );
print_r($result);
?>