timber/timber

@rgcouk The starting point for working with WooCommerce seems to be http://timber.github.io/timber/#woocommerce. That’s probably the only standard that exists.

When using Timber, you don’t necessarily have to convert everything to Twig. You could still use PHP. If you need the output of a PHP file in a Twig file, something like this might work:

ob_start();
include ('path/to/mini-cart.php');

$context['minicart'] = ob_get_contents();
ob_end_clean();

As you assumed, importing PHP code directly into Twig won’t work, so you’d have to convert it to Twig. Something like this might work:

$context['cart'] = WC()->cart;

In your Twig file you could maybe do something like this:

{% if not cart.is_empty }
    {% do action( 'woocommerce_before_mini_cart_contents' ) %}

    {% for cart_item_key, cart_item in cart.get_cart %}
        {% set product = fn('apply_filters', 'woocommerce_cart_item_product', cart_item.data, cart_item, cart_item_key)}

        {# … #}
    {% endfor %}
{% endif %}