Actually, I need this interpretation {7. 8. "f"} for writing parser of javascript queries��which is used in MongoDB shell, to be able to execute this with ��MongoQuery Pharo class.
Maybe, you could help me how to implement it?

Do you mean parsing Json syntax?��
https://www.mongodb.com/json-and-bson

Maybe this is useful��
https://ci.inria.fr/pharo-contribution/job/EnterprisePharoBook/lastSuccessfulBuild/artifact/book-result/NeoJSON/NeoJSON.html