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Change discussion of derive/annotations/traits to match reorg

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Carol (Nichols || Goulding) 2016-07-21 21:53:08 -04:00
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src/ch05-00-structs.md
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@ -210,7 +210,7 @@ Our function signature for `distance()` now says exactly what we mean: it
calculates the distance between two `Point`s. And rather than `0` and `1`,
we’ve got back our `x` and `y`. This is a win for clarity.
There’s one other thing that’s a bit strange here, this annotation on our
There’s one other thing that’s a bit strange here, this stuff above the
`struct` declaration:
```rust,ignore
@ -218,7 +218,10 @@ There’s one other thing that’s a bit strange here, this annotation on our
struct Point {
```
We haven’t yet talked about traits, but we did talk about `Debug` when we
discussed arrays. This `derive` attribute allows us to tweak the behavior of
our `Point`. In this case, we are opting into copy semantics, and everything
that implements `Copy` must implement `Clone`.
This is an annotation that tells the compiler our struct should get some
default behavior for the `Debug`, `Copy`, and `Clone` traits. We talked about
`Debug` when we discussed arrays-- this lets us print out the `struct` and all
its fields when we use an instance of the struct with `println!`'s `{:?}`. We
talked about marking that types can be `Copy` and `Clone`-able in Chapter XX
when we discussed ownership. We'll continue exploring annotations and the
behaviors you can `derive` in Chapter XX.