{
    "effect": "permit",
    "principal": {
        "op": "in",
        "slot": "?principal"
    },
    "action": {
        "op": "in",
        "entities": [
            {
                "type": "Action",
                "id": "view"
            },
            {
                "type": "Action",
                "id": "comment"
            }
        ]
    },
    "resource": {
        "op": "in",
        "slot": "?resource"
    },
    "conditions": [
        {
            "kind": "unless",
            "body": {
                "==": {
                    "left": {
                        ".": {
                            "left": {
                                "Var": "resource"
                            },
                            "attr": "tag"
                        }
                    },
                    "right": {
                        "Value": "private"
                    }
                }
            }
        }
    ]
}