Hah, synchronicity! Yes, I was drafting an email with a suggestion for
something similar, although i used a __MATCH_OR_DIE expression form
that looked like a cast, and an unchecked exception.
Did I just imagine it, or was there a suggestion for something like
this in the past?:
var Point(var x, var y) = ...
Close. We have experimented with various forms of "imperative match".
Our first attempt was something like:
let P = e;
where P had to be total. This was later refined to something like
let P = e
else { ... }
where the else block had to either throw, or assign to all the bindings
in the pattern.
We later started to feel that (a) `let` was unnecessarily fussy, and (b)
casting it like a statement meant that we lost some other
opportunities. So we shifted towards something like
P = e
for suitably constrained patterns, on the observation that
T t = e;
which is currently a local variable assignment, could equally well be
interpreted as matching the type pattern `T t` to the expression. So we
could retroactively reinterpret `P = e` (at least for type and
deconstruction patterns) as an imperative match, rather than a
declaration-with-initializer, if we want. That's nice, but that kind of
forecloses on the else clause.
Regardless, the semantics here would be match-or-not, rather than
match-or-die. I think if you wanted match-or-die, you'd have to
specifically ask for it somehow (such as a try- construct.)
