E2E: Erik Meijer and Burton Smith - Concurrency, Parallelism and Programming

Good stuff.

In terms of exceptions as values, at the 500 foot level, it would seem if Object had a new property to "hold" exception, the type system would/could just work.  You could use normal try/catch or not as needed.  In a message passing model, I would tend to think all non-void functions need to return a type even if that type is an exception. 

var x = foo(0);          // foo returns exception inside Int object.
Write(x.ToString()); // x.ToString() returns exception text inside object.
if (x.IsException())   // Can test any object (including value types) for exception.
    Write("x holds exceptional value.");
var y = x + 1;     // Statement exception on eval here because x "contains" exceptional x.
return y;      // Return normal result.

On "y = x + 1" does runtime throw or just return "exceptional" x.  How to handle void functions?

Here is small token of my appreciation Erik: