structural type equality

structtypeeq.pony

trait Ate
  fun food(): String val => "Something"
  
interface Named
  fun name(): String val => "Somebody"
  
type NamedEater is (Ate & Named)

class Charlie is (Ate & Named)
  new create() =>
    None
  fun name(): String val => "Charlie"

actor Main
  var _env: Env
  new create(env: Env) =>

    _env = env
    var c = Charlie
    use_named(c)

  fun use_named(x : NamedEater) =>
    _env.out.print(x.name() + " ate " + x.food())