Is it possible to set a dynamic default value for a field?

Hello,
I want to set a default value for the data property of the pagination object based on the collection item name. I tried this but it didn’t seem to work

  - name: "subcategories"
    label: "Subcategories"
    folder: "_site/categories"
    create: true
    slug: "{{slug}}"
    fields:
      - {label: "Name", name: "name", widget: "string"}
      - label: "Pagination"
        name: "pagination"
        widget: "object"
        fields:
          - {label: "Data", name: "data", widget: "string", default: 'collections.{{fields.name}}'}
          - {label: "Size", name: "size", widget: "number", default: 5}

Is there some way to achieve it?

Linking to the answer in Slack:
https://netlifycms.slack.com/archives/CPRR0PQ9E/p1596526133098500?thread_ts=1596525743.094100&cid=CPRR0PQ9E

Hi @DINO, using string templates in default values is not possible yet. Default values are evaluated before a new entry is created so using another field will require some thought. However, you could write a custom widget that does that.