Setting and updating variables in loop

[NielDuysters]

I have a loop which outputs some items. However, if no items are outputted (because there are none) I want to show "no items". Basically I need to be able to set and update variables in Askama.

My code:

<div id="foodmenu">
            {% for category in categories %}
            
                //PSEUDO
                {% set hash_dishes = False %}

                <div class="foodmenu-category">
                    <span class="foodmenu-category-title">{{ helpers::capitalize(category.1) }}</span>
                    <div class="foodmenu-item-container">
                        {% for dish in restaurant.dishes %}
                            {% if !dish.is_disabled %}

                                /////////////////////////////////
                                {% hash_dishes = True %}
                            
                                {% if dish.category.is_some() && dish.category.unwrap() == category.0 %}
                                    <div class="foodmenu-item" data-id="{{ dish.id }}">
                                        <span class="foodmenu-item-name">{{ dish.name }} <img alt="Toevoegen" class="foodmenu-item-add" src="/assets/media/images/icons/add.png"></span>
                                        <span class="foodmenu-item-description">{{ dish.description }} <img alt="(?)" class="foodmenu-item-description-info" src="/assets/media/images/icons/question-mark.png"></span>
                                        <span class="foodmenu-item-price">&euro; {{ format!("{:.2}", dish.variations[0].price).replace(".", ",") }}</span>
                                        {% if dish.image.is_some() %}
                                            <img alt="" class="foodmenu-item-image" src="{{ dish.image.as_ref().unwrap() }}">
                                        {% endif %}
                                    </div>
                                {% endif %}
                            {% endif %}
                        {% endfor %}

                        ///////////////////////
                        {% if !hash_dishes %}
                            No dishes.
                        {% endif %}

                    </div>
                </div>
            {% endfor %}
        </div>

[Kijewski]

You could probably use for-else: #518

{% for dish in restaurant.dishes if !dish.is_disabled %}
    {% if dish.category.is_some() && dish.category.unwrap() == category.0 %}
        ...
    {% endif %}
{% else %}
    No dishes.
{% endfor %}

[NielDuysters]

I know about for-else but that is not possible in this case. I loop over all the categories, and inside that loop I go over all the dishes, check the category of each dish AND if dish.category == category_of_loop I output the dish.

[Kijewski]

Then you could use a Cell:

{% set hash_dishes = std::cell::Cell::new(false) %}

{% for dishes in restaurant %}
    {% for dish in dishes %}
        {% if dish.is_tasty() %}
            {% let _ = hash_dishes.set(true) %}
            dish
        {% endif %}
    {% endfor %}
{% endfor %}

{% if !hash_dishes.get() %}
    no dishes
{% endif %}

[NielDuysters]

Thanks a lot! This works perfectly.

[Kijewski]

You're welcome! :)