curl -X PUT "localhost:9200/test0" -H 'Content-Type: application/json' -d'       

{
    "mappings" : {
        "_doc" : {
            "properties" : {
                "field0": {"type": "long"},
                "field1" : {   "type": "nested",
                                "properties": {
                                        "nested1": {
                                           "type": "integer"}
                                }
                           }
            }
        }
    }
}

 curl -X PUT "localhost:9200/test0/_doc/1" -H 'Content-Type: application/json' -d'
{
    "field0" : 12, "field1": [{"nested1":1}]                                 
}   
'  

curl -X POST "localhost:9200/_scripts/painless/_execute" -H 'Content-Type: application/json' -d'
{
  "script": {
    "source": "return doc[\"field0\"].value    ",
    "params": {
      "number": 1
    }
  },
  "context_setup": {
    "index": "test0",
    "document": {
      "field0": 3,
      "field1": [
        {
          "nested1": 2
        }
      ]
    }
  },
  "context": "score"
}

'

{"result":0.0}