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Expand further on <> syntax in TRPL. #27538

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Aug 5, 2015
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Expand further on <> syntax in TRPL. #27538

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14 changes: 12 additions & 2 deletions src/doc/trpl/lifetimes.md
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Expand Up @@ -77,8 +77,18 @@ Before we get to that, though, let’s break the explicit example down:
fn bar<'a>(...)
```

This part declares our lifetimes. This says that `bar` has one lifetime, `'a`.
If we had two reference parameters, it would look like this:
We previously talked a little about [function syntax][functions], but we didn’t
discuss the `<>`s after a function’s name. A function can have ‘generic
parameters’ between the `<>`s, of which lifetimes are one kind. We’ll discuss
other kinds of generics [later in the book][generics], but for now, let’s
just focus on the lifteimes aspect.

[functions]: functions.html
[generics]: generics.html

We use `<>` to declare our lifetimes. This says that `bar` has one lifetime,
`'a`. If we had two reference parameters, it would look like this:
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This might be a bit deceptive -- a function can have many more lifetimes that aren't declared thanks to elision.

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From a technical perspective I each function can have multiple lifetime parameters, but from the perspective of just explaining syntax I think it's fine to assume that "lifetime parameter" is the same as "explicitly declared lifetime parameter". Elision kinda fits into the same system later on, so I don't think that we're going to confuse anyone from this.



```rust,ignore
fn bar<'a, 'b>(...)
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