Setting values in a child object from a parent object

[jmgilman]

class A {
    name: String
    b: Mapping<String, B>
}

class B {
    name: String
}

In this simplified example, is it possible to have B.name default to the value of A.name if it's not specified? I understand the existence of the Mapping is what complicates things here, but it's at the crux of the question. It's possible I'm using the wrong type here.

[HT154]

If I'm interpreting your goal correctly, I think you want something like this:

class A {
  name: String
  local _a = this // this "captures" this A so it can be used unambiguously in inner scopes
  b: Mapping<String, B> = new {
    default {
      name = _a.name
    }
  }
}

class B {
  name: String
}

So writing this:

test = new A {
  name = "test"
  b {
    ["abc"] {}
    ["def"] { name = "def" }
  }
}

Produces

test {
  name = "test"
  b {
    ["abc"] {
      name = "test"
    }
    ["def"] {
      name = "def"
    }
  }
}

[jmgilman]

Ah, it was the default syntax that I didn't know of. Thanks!

[HT154]

No problem! It's worth noting that default isn't actually special syntax, it's just a regular property of the Mapping instead of a k/v entry. I wrote a little about how this all works (and link some relevant documentation) here: #1053 (comment)