named arguments to set fields in a constructor

[sigmundch]

I am not sure if this feature request is worth it, but I wanted to share the idea, so here it is:

What if we take generated messages and make a constructor that takes as arguments the actual fields from the proto buff? for example:

message A {
  required someField = 1;
  optional otherField = 2;
}

generates:

class A extends GeneratedMessage {
  A.filled(this.someField, {this.otherField});
}

I just often see patterns where developers have all the data they need to fill in, and end up writing code like:

  new A()
      ..someField = a
      ..otherField  = b

instead of:

  new A(a, otherField: b)

[skybrian]

I've been thinking of doing this along with support for read-only protobufs. I'm not working on it, though.

(I think it would be better to use named parameters for all fields. Protobuf fields usually don't have a logical order.)

[gamebox]

I'd like to take this on, if you are interested in contributions. I've already signed the Google contributor agreement.

[aloisdeniel]

I agree !

This would be a lot easier to write embedded affectation IMO. Only using named parameters could be even better too (like Flutter API). You can make named parameter @required with meta package.

I find that this kind of instantiation is quite a mess (too many parenthesis and dots) :

Person()
      ..name = "John"
      ..address = (Address()
         ..street = 5
         ..label = "Baker street"
         ..country = (Country()
             ..code = "en"
             ..name = "england"
        )
    )

The following feels a lot more natural to me, and more aligned with traditional dart APIs :

Person(
  name: "John",
  address: Address(
      street: 5,
      label: "Baker street",
      country: Country(code: "en", name: "england")
  )
)