Comment by jameshart

I can't help thinking that

   [
     { "op": "replace", "path": "/baz", "value": "boo" },
     { "op": "add", "path": "/hello", "value": ["world"] },
     { "op": "remove", "path": "/foo"}
   ]

would be better described as

     value["baz"] = "boo";
     value["hello"] = ["world"];
     delete value["foo"];

Why go to the trouble of defining your grammar as a strict subset of JSON documents, which are themselves written using a strict subset of JavaScript syntax, when you could just limit yourself instead to the strict subset of JavaScript syntax that encapsulates the operations you actually want to perform?