On 09/25/2013 06:37 PM, Diggory Hardy wrote:
Hi,
On Wednesday 25 September 2013 08:29:17 Patrick Walton wrote:
On 9/25/13 6:32 AM, Alexander Sun wrote:
Multiple return values
if has a function like this:
fn addsub(x : int, y : int) -> (int, int) {
return (x+y,x-y);
}
them, this is valid:
let (b,c) = addsub(x, y);
but this is invalid;
let b:int =0;
let c:int =0;
(b,c) = addsub(x, y);
also invalid:
let (b,c) = (0, 0);
(b,c) = addsub(x, y);
If we did this, we wouldn't know whether to parse a pattern or an
expression when starting a statement. This isn't fixable without trying
to define some sort of cover grammar that covers both expressions and
patterns, like ECMAScript 6 does. I don't know if this would work in Rust.
Are there any plans to support something like:
assign (b,c) = addsub(x,y);
for existing b,c? The best I could come up with is:
match two_nums(2) {
(x,y) => {a=x;b=y;}
}
Not that I need this; just curious.
I had the idea once to reuse the `in` keyword for that:
let mut a = 0; let mut b = 1;
in (a, b) = (b, a);
No idea how feasible that would be, though.
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