Shorthand for "pattern matching" on an object parameter

One thing I really miss when writing jsonnet after writing Nix for a while is the ability to deconstruct an object being passed in as a parameter. For example:

``` nix
{ a, b, c }: a + b + c
```

is a one-parameter lambda (arguably the only sort that matters!) that expects the caller to pass it a dict with those three keys in it. You can also set defaults and match on the aggregate.

Would it be possible to get something similar in jsonnet?