feature request - key of object within parent object

I've found myself often doing things that require the key of the object I'm currently in. Here's an example:

```jsonnet
top: {
myThing: {
name: "myThing" // this is the key of the current object with "top"
}
}
```

desired:

```jsonnet
top: {
myThing: {
name: keyOf(self, $)
}
}
```

I have no idea if this is reasonably possible, or maybe there's a better way to go about doing this?