[E-Lang] Hydro & E operator expansions

[Dan Bornstein]

Mark S. Miller writes:
>5) Generalize C's op= syntax to apply to general message passes, so that
>    foo msg= (bar, baz)
>would expand to
>    foo := foo msg(bar, baz)
>in which case we could write our update as
>    map with= (key, newValue)

The more I think about this one, the more I like it. The one thing that I'm
wondering, though, is how this should interact with eventual sends. Should
I be able to say something like "set x to be the promise that will
eventually be the result of having sent message foo to
x-as-it-currently-is"? That is, should there be a shorthand for things of
this form:

    x := x <- foo (bar, baz)

?

I know, it's kinda wacky.

-dan