What are some best practices for implementing nested function calls in PHP?

When implementing nested function calls in PHP, it's important to ensure that the functions are properly structured and organized to avoid confusion and maintain readability. One best practice is to break down complex nested function calls into separate, well-named functions to improve code maintainability. Additionally, using proper indentation and commenting can help make the code more understandable for other developers.

// Example of implementing nested function calls in PHP
function calculateTotal($price, $quantity) {
    return applyTax(calculateSubtotal($price, $quantity));
}

function calculateSubtotal($price, $quantity) {
    return $price * $quantity;
}

function applyTax($subtotal) {
    $taxRate = 0.10; // 10% tax rate
    return $subtotal * (1 + $taxRate);
}

$price = 10;
$quantity = 5;
$total = calculateTotal($price, $quantity);

echo "Total cost: $" . $total;