test_parse_block_liquid.rb

require 'liquid'
require 'json'

liquid = <<-DOC
{% block_settings %}
{
  "name": "Ken block",
  "settings": [
    {
      "type": "text",
      "id": "texta",
      "label": "Main Label"
    },
    {
      "type": "text",
      "id": "textb",
      "label": "Sub-label"
    }
  ]
}
{% endblock_settings %}

{% block_content %}
hello {{ block.texta | default: 'foobar' }} and {{ block.textb | default: 'second' }}
foobar
{% endblock_content %}
DOC


class BlockSettings < Liquid::Block
  def to_s
    nodelist.first
  end

  def schema
    JSON.parse to_s
  end
end

class BlockContent < Liquid::Block
  def to_s
    nodelist.first
  end
end

Liquid::Template.register_tag('block_settings', BlockSettings)
Liquid::Template.register_tag('block_content', BlockContent)

template = Liquid::Template.parse(liquid)
template.root.nodelist.each do |node|
  @schema = node.schema if node.is_a? BlockSettings
  @liquid_body = node if node.is_a? BlockContent
end

p @schema
p @liquid_body