Register field definitions are confusing due to vacuous types

[phausler]

Register fields are required to specify a type but common usage will use an as: parameter. This means that the type that is written for a given field is not really used. Instead it is a type information for storing via an un-inhabited enumeration.

@ReadWrite(bits: 0..<3, as: TestValues.self)
public var someField: Test

this expands in the register and the field to:

public var someField: Test {
    get {
        fatalError()
    }
}

public  enum Test: ContiguousBitField {

            public  typealias Storage = UInt8

            public  static let bitRange = 0 ..< 3
}

instead it could be more canonically written in standard swift parlance as:

@ReadWrite(bits: 0..<3)
public var someField: TestValues

which can expand (by using the name of the field instead of the name of the type)

public  enum SomeField: ContiguousBitField {

            public  typealias Storage = UInt8

            public  static let bitRange = 0 ..< 3
}

[fumoboy007]

I agree! Swapping the projected type and the descriptor type would make it feel more natural.

As I wrote here, the register field macro could even have a generatedDescriptorType property to allow the developer to specify the generated type name. (It would be nice for the macro to automatically generate a name if the macro property was omitted though.)

@ReadWrite(bits: 0..<3, generatedDescriptorType: Test.self)
public var someField: TestValues