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Reference correct fn during lifetime ellision

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Sean T Allen 2015-01-22 13:00:15 -05:00
parent 5d2056a7e3
commit 42cbd7a9bd
1 changed files with 8 additions and 8 deletions
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16
src/doc/trpl/ownership.md
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@ -244,8 +244,8 @@ three. The ownership system in Rust does this through a concept called
Remember the function that borrowed an `i32`? Let's look at it again. Remember the function that borrowed an `i32`? Let's look at it again.
```rust ```rust
fn add_one(num: &i32) -> i32 { fn add_one(num: &mut i32) {
*num + 1 *num += 1;
} }
``` ```
@ -255,8 +255,8 @@ cover the others later. Without eliding the lifetimes, `add_one` looks like
this: this:
```rust ```rust
fn add_one<'a>(num: &'a i32) -> i32 { fn add_one<'a>(num: &'a mut i32) {
*num + 1 *num += 1;
} }
``` ```
@ -278,12 +278,12 @@ fn add_two<'a, 'b>(...)
Then in our parameter list, we use the lifetimes we've named: Then in our parameter list, we use the lifetimes we've named:
```{rust,ignore} ```{rust,ignore}
...(num: &'a i32) -> ... ...(num: &'a mut i32)
``` ```
If you compare `&i32` to `&'a i32`, they're the same, it's just that the If you compare `&mut i32` to `&'a mut i32`, they're the same, it's just that the
lifetime `'a` has snuck in between the `&` and the `i32`. We read `&i32` as "a lifetime `'a` has snuck in between the `&` and the `mut i32`. We read `&mut i32` as "a
reference to an i32" and `&'a i32` as "a reference to an i32 with the lifetime 'a.'" mutable reference to an i32" and `&'a mut i32` as "a mutable reference to an i32 with the lifetime 'a.'"
Why do lifetimes matter? Well, for example, here's some code: Why do lifetimes matter? Well, for example, here's some code: