In S02 it is writ, "The key type of a hash may be specified as a shape trait--see S09."
However, S09 is rather brief on hashes, and although it shows using a type inside the curlies, it never talks about shape traits or anything else. Am I do understand that it pretty much does all the same stuff that Array does? More globally, nothing is said much about parameters to types. It shows an example like Array[of=>T] but never discusses the syntax of defining parameterized types or anything. Is there a paper or discussion on that I could read? Thanks, --John