There are a few roads not taken: “switch ()” with boolean
case expressions has not showed itself worthy yet.
Yep, this one can sit on the shelf.
I’d also like to point out “switch (a, b)” as a possible area
of future work for switch, where the thing after “switch” is a
more generalized argument expression
ML supports this, because it just treats the operand as a tuple, and
automatically destructures tuples. The killer use case is, of course,
FizzBuzz:
switch (n % 3, n % 5) {
case (0, 0) -> "FizzBuzz";
case (0, _) -> "Fizz";
case (_, 0) -> "Buzz";
default -> n.toString();
}
1. Allow certain simple statements after “->” without
requiring “{ … }” wrappers.
We already do this with `throw`, but could extend. I'm waiting for
Valhalla to make `void` a type, and then see how painful it is to merge
statement switch with void expression switch. (Now that we've
totalized, it's easier.)
2. Allow a way to add a given case to the “remainder”
set, to be treated similarly to “built-in” remainder
processing. Proposed syntax: “throw;” as in
“case null->throw;”. (Raises the question of whether
to support such a notation outside of switch,
but we could just say “no”. Or spell it “throw default;”
or “throw assert”.)
There's two aspects of this: matching on the remainder (case else?), and
denoting the default throw.
