Instantiate structs with only one fragment directly

[Mathias Quintero]

This example should be valid:

struct CountryMapPin {
    @GraphQL(Covid.Country.cases)
    var cases: Int

    @GraphQL(Covid.Country.info.latitude)
    var latitude: Double?

    @GraphQL(Covid.Country.info.longitude)
    var longitude: Double?
}

struct ContentView: View {
    @GraphQL(Covid.countries)
    var pins: [CountryMapPin]

    var body: some View {
         MapView(pins: pins).frame(height: 400)
    }
}

Proposal

We solve this by adding the following extension to every struct that has a single fragmentl:

extension CountryMapPin: Fragment {
    typealias UnderlyingType = Country.UnderlyingType
}

extension CountryMapPin.Country { 
    func countryMapPin() -> CountryMapPin { 
        return CountryMapPin(country: self) 
    }
}

In code generation add an extra operation to implicitly convert. Create it during resolution.

[Mathias Quintero]

First draft of this proposal is in 157bdb4

It appears to work fine simple scenarios. I have to perform more testing on these scenarios before a release:

• Optionals
• Array
• Array + Optional combinations
• Connections
• Mutations