I made changes as you told me:
1 pub trait TupleVal<T> {
2 pub pure fn _1(&self) -> &self/T;
3 /*pub pure fn _2(&self) -> &self/T;*/
4 }
5
6 impl <T>(T, T): TupleVal<T> {
7 pure fn _1(&self) -> &self/T {
8 let &(a, _) = self;
9 &a
10 }
11 /*pure fn _2(&self) -> &self/T {*/
12 /*let &(_, b) = self;*/
13 /*&b*/
14 /*}*/
15 }
16
17 fn main() {
18 let pair = (1, 2);
19 let left = *pair._1();
20 io::println(fmt!("pair left: %u", left));
21 /*let r = pair._2();*/
22 }
But:
test.rs:9:9: 9:10 error: illegal borrow: borrowed value does not live long
enough
test.rs:9 &a
^
test.rs:7:33: 10:5 note: borrowed pointer must be valid for the lifetime &self
as defined on the block at 7:33...
test.rs:7 pure fn _1(&self) -> &self/T {
test.rs:8 let &(a, _) = self;
test.rs:9 &a
test.rs:10 }
test.rs:7:33: 10:5 note: ...but borrowed value is only valid for the block at
7:33
test.rs:7 pure fn _1(&self) -> &self/T {
test.rs:8 let &(a, _) = self;
test.rs:9 &a
test.rs:10 }
error: aborting due to previous error
Did I miss something?
On Feb 2, 2013, at 9:08 AM, Niko Matsakis <n...@alum.mit.edu> wrote:
> You need "let (a, _) = *self" or "let &(a, _) = self". self is a pointer to
> a tuple, not a tuple.
>
>
> Niko
>
> Alexander Stavonin wrote:
>>
>> Thank you! But I still can not compile it:
>>
>>
>> 1 pub trait TupleVal<T> {
>> 2 pub pure fn _1(&self) -> &self/T;
>> 3 pub pure fn _2(&self) -> &self/T;
>> 4 }
>> 5
>> 6 impl <T>(T, T): TupleVal<T> {
>> 7 pure fn _1(&self) -> &self/T {
>> 8 let (a, _) = self;
>>
>> 9 a
>> 10 }
>> 11 pure fn _2(&self) -> &self/T {
>> 12 let (_, b) = self;
>> 13 b
>> 14 }
>> 15 }
>>
>> test.rs:8:12: 8:18 error: mismatched types: expected `&self/('a,'a)`, found
>> tuple
>> test.rs:8 let (a, _) = self;
>> ^~~~~~
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