New Query Syntax Docs

[olbrichj]

I'm trying to figure out how to use Meow 2.0.2. By now I figured out how to save but I'm totally lost regarding the Queries.

class Test: Model {
    var _id = IdObject()
    var symbol: Symbol
}

class Symbol: Codable {
    var name: String
    var number: Int
}

With this setup I'm trying to find documents by name or number (or even both).

let context = manager?.makeContext()
let query: Query = "symbol.name" == "Test"
let result = try? context?.findOne(Test.self, where: query).wait()

Or trying to have name on toplevel:

class Test: Model {
    var _id = IdObject()
    var name: String
}

let context = manager?.makeContext()
let query: Query = "name" == "Test"
let result = try? context?.findOne(Test.self, where: query).wait()

All of these result in nil. I've also tried to create the corresponding syntax:

[
  "name" : [
    "$eq" : 
    "Test"
  ]
]

Which also didn't work. So I'm wondering... what is the correct way to query for documents in Meow 2.0?

I would be willing to help and write some docs, but I'd need to know how to use Meow first :D

[Joannis]

There are two reasons you could be getting nil. Either manager == nil or you don't have an entity with "name" == "Test". The query is completely fine :)

[olbrichj]

I will check again, when I'm back from work. The manager is present, as I use the same one to create the entries in MongoDB (which I can also find).

Regarding the Query syntax. Is the above syntax also correct?
"symbol.name" == "Test"

[Joannis]

The syntax is fine. I'm wondering, why is the manager is optional

[olbrichj]

Oh that is just a relict of my testing trying to figure out how this works :D The optional will be removed in my next try

[olbrichj]

So it seems like this is a bug in Xcode or llvm. It does return a document, but Xcode still displays it as nil. Unwrapping changes everything.

But I have another question regarding the syntax. If I want to compare a value with a codable struct, is there any way to not compare every value explicitly?

Given this structure:

class Test: Model {
  var _id = IdObject()
  var address: Address
}

struct Address: Codable {
  var street: String
  var country: Country
}

enum Country: String, Codable {
  case australia
}

I can compare it explicitly:

let query: Query = ("address.street" == testInstance.address.street) && ("address.country" == testInstance.address.country.rawValue

What I'm looking for is something like this

let query: Query = "address" = testInstance.address

Furthermore I've seen the old syntax is like this:

Test.findOne() { test in
  return test.address.strees = "foo"
}

Is there something similar? I found it for saving but didn't see anything for querying.

testInstance.save(to: context)

Last but not least, regarding the docs. Is there a specific format or a template to orientate? :)

[Joannis]

The current syntax would be like this:

let query: Query = "address.street" == Country.australia.rawValue

However, I think we have code that allows you to use raw enums directly, too:

let query: Query = "address.street" == Country.australia

[Joannis]

I guessed why not, so I implemented what I think is a good design of this snippet in Meow 3:

Test.findOne() { test in
  return test.address.strees = "foo"
}

[olbrichj]

That snippet for querying looks really neat :) Would also be great for .find().

Regarding the raw enum query I get the following error:

Cannot convert value of type 'Country' to expected argument type 'Primitive?'

I tried extending the enum with Primitive, which doesn't result in a compile error but instead a runtime exception:

Fatal error: Currently unsupported type []: file .build/checkouts/BSON/Sources/BSON/Document/Document+Dictionary.swift, line 175