Case 1: set new code/valueType fields:

Request

				
					{
    "blockOptions": {
        "method": {
                "name": "setExpression",
                "args": {
                "name": "name",
                "valueType": "valueType",
                "metadata": "metadata",
                "code": "code"
            },
        }
    },
    "blockType": "then",
    "fields": [
        {
            "name": "name",
            "type": "string",
            "value": "expression.name"
        },
        {
            "name": "code",
            "type": "string",
            "value": "return (some Lua code calculations here)"
        },
        {
            "name": "valueType",
            "type": "string",
            "value": "int"
        },
        {
            "name": "metadata",
            "type": "object",
            "value": {"key":"value"}
        }
    ]
}