Query <- JsonObject | MongoDbQuery
MongoDbQuery <- Db + Separator + Collection + Separator + Operation
Db <- "db"
Collection <- Not(Operation) | (Separator + Collection)*
Operation <- Find
Find <- "find" + "(" + JsonObject + ")"
Separator <- WhiteSpace* + "." + WhiteSpace*

public Rule Query() {
        return FirstOf(
                Sequence(Db(), Separator(), Collection()),
                JsonObject()
        );
    }

    public Rule Db() {
        return String("db");
    }

    @SuppressWarnings("InfiniteRecursion")
    public Rule Collection() {
        return FirstOf(TestNot(Operation()), Sequence(Separator(), Collection()));
    }
    
    public Rule Operation() {
        return FirstOf(
                Find(),
                FindOne()
        );
    }
    
    public Rule Find() {
        return Sequence(
                String("find"),
                String("("),
                JsonObject(),
                String(")")
        );
    }

    public Rule Separator() {
        return Sequence(ZeroOrMore(WhiteSpace()), '.', ZeroOrMore(WhiteSpace()));
    }

    public Rule WhiteSpace() {
        return OneOrMore(AnyOf(" \t\r\f\n"));
    }