WIP - Support {% render obj %}

[catlee]

We would like to add support to the render tag so that it can render externally specified blocks by passing in the block object to the render tag.

For example, in a section rendering a set of blocks:

{% for block in section.blocks %}
  {% case block.type %}
  {% when "title" %}
    {{ block.settings.title }}
  {% when "@app" %}
    {% render block %}
  {% endcase %}
{% endfor %}

We've found this useful in Shopify to render 3rd party extensions contained in "app blocks": https://shopify.dev/themes/architecture/sections/section-schema#render-app-blocks

[sebastienros]

Wouldn't it make more sense by using {{ obj }} instead? The render tag was introduced also for its caching semantics which I think this PR is breaking.

[catlee]

We are currently using {% render block %} in Shopify for rendering app blocks: https://shopify.dev/themes/architecture/sections/section-schema#render-app-blocks

We did also consider using constructs like {{ obj }} or {{ obj.render }} but ultimately decided that {% render obj %} was more appropriate for a few reasons:

• Using a tag gives us the ability to pass arguments if needed, {% render obj, foo: bar %}
• We already have {% render 'snippet' %} tag which renders a local template file. Rendering application-defined content using the render tag seems like a natural extension of the behaviour here.

I'm hopeful that this functionality will be generally useful, by allowing application specific drops to render themselves.

[sebastienros]

We already have {% render 'snippet' %}

And they explicitly made 'snippet' be only string literal in render when it was introduced to "fix" the include tag so the template could be cached.

I still like the concept but I am concerned it won't be accepted in this form. Might even be easier to sell it in the now defunct include tag ...