Eval script inside field

[opak]

Hello, i have a question how to eval script which can be stored inside a field.

For example, i want to define rules for calculation inside documents. Let's see on this mapping:

index: rules

{
  "properties": {
    "price_rule":  { "type": "keyword" }
  }
}

Then i add document:

curl -X PUT localhost:9200/rules/_doc/1 -d '{"price_rule": " if (params.Age <= 60) { return 20 } else { return 30}"}' -H "Content-Type: application/json"

And i want todo a request for search, where i can send para age and see which documents has price_rule > 20 as example.

{
  "query": {
    "bool" : {
      "filter" : {
        "script" : {
          "script" : {
            "source" : "doc['price_rule'].value",
            "lang"   : "painless",
            "params" : {
              "Age" : "60"
            }
          }
        }
      }
    }
  }
}

How i can eval script inside field and pass params?