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Fix vector/array/slice terminology in manual. #16825

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48 changes: 25 additions & 23 deletions src/doc/rust.md
Original file line number Diff line number Diff line change
Expand Up @@ -3564,34 +3564,36 @@ let (a, b) = p;
assert!(b != "world");
~~~~

### Vector types
### Vector, Array, and Slice types

The vector type constructor represents a homogeneous array of values of a given type.
A vector has a fixed size.
(Operations like `vec.push` operate solely on owned vectors.)
A vector type can be annotated with a _definite_ size, such as `[int, ..10]`.
Such a definite-sized vector type is a first-class type, since its size is known statically.
A vector without such a size is said to be of _indefinite_ size,
and is therefore not a _first-class_ type.
An indefinite-size vector can only be instantiated through a pointer type,
such as `&[T]` or `Vec<T>`.
The kind of a vector type depends on the kind of its element type,
as with other simple structural types.
Rust has three different types for a list of items:

Expressions producing vectors of definite size cannot be evaluated in a
context expecting a vector of indefinite size; one must copy the
definite-sized vector contents into a distinct vector of indefinite size.
* `Vec<T>`, a 'vector'
* `[T ..N]`, an 'array'
* `&[T]`, a 'slice'.

An example of a vector type and its use:
A vector is a heap-allocated list of `T`. A vector has ownership over the data
inside of it. It is also able to grow and change in size. It's important to note
that `Vec<T>` is a library type, it's not actually part of the core language.

~~~~
let v: &[int] = &[7, 5, 3];
let i: int = v[2];
assert!(i == 3);
~~~~
An array has a fixed size, and can be allocated on either the stack or the heap.

A slice is a 'view' into a vector or array. It doesn't own the data it points
to, it borrows it.

An example of each kind:

```{rust}
let vec: Vec<int> = vec![1, 2, 3];
let arr: [int, ..3] = [1, 2, 3];
let s: &[int] = vec.as_slice();
```

As you can see, the `vec!` macro allows you to create a `Vec<T>` easily. The
`vec!` macro is also part of the standard library, rather than the language.

All in-bounds elements of a vector are always initialized,
and access to a vector is always bounds-checked.
All in-bounds elements of vectors, arrays, and slices are always initialized,
and access to a vector, array, or slice is always bounds-checked.

### Structure types

Expand Down