I'm very new to Julia, so my apologies for the bits I inevitably get wrong.
As far as I can tell, Julia has no notion of interface, i.e. "if you declare your data type a subtype of Foo, you also must/should implement these functions on the type". This seems like a pretty significant lack to me - it turns the (otherwise quite lovely) type system into essentially tagged duck typing. There are a few packages that implement their own version of interfaces (and it speaks well of Julia that this is possible!), but they do so with very different semantics and don't expose any sort of general interface-construction machinery. Are there any proposals for an interface framework as part of the standard library?
