// PHP Function
function custom_greeting($atts) {
    // Extract shortcode attributes
    $atts = shortcode_atts(
        array(
            'name' => 'Guest',
            'age' => 0
        ),
        $atts
    );

    // Generate custom greeting
    $greeting = "Hello, {$atts['name']}! ";
    if ($atts['age'] > 0) {
        $greeting .= "You are {$atts['age']} years old.";
    } else {
        $greeting .= "We don't know your age.";
    }

    return $greeting;
}

// Shortcode
add_shortcode('greeting', 'custom_greeting');