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auto merge of #14567 : cburgdorf/rust/patch-2, r=brson

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This rewrites the example to also be more aligned with
the same example given in the main tutorial.
This commit is contained in:
bors 2014-05-31 20:01:45 -07:00
commit ee97698f85
1 changed files with 5 additions and 4 deletions
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9
src/doc/guide-lifetimes.md
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@ -67,7 +67,7 @@ Now we can call `compute_distance()`:
# let on_the_stack : Point = Point{x: 3.0, y: 4.0};
# let on_the_heap : Box<Point> = box Point{x: 7.0, y: 9.0};
# fn compute_distance(p1: &Point, p2: &Point) -> f64 { 0.0 }
compute_distance(&on_the_stack, &*on_the_heap);
compute_distance(&on_the_stack, on_the_heap);
~~~
Here, the `&` operator takes the address of the variable
@ -77,9 +77,10 @@ value. We also call this _borrowing_ the local variable
`on_the_stack`, because we have created an alias: that is, another
name for the same data.
For the second argument, we need to extract the contents of `on_the_heap`
by derefercing with the `*` symbol. Now that we have the data, we need
to create a reference with the `&` symbol.
In the case of `on_the_heap`, however, no explicit action is necessary.
The compiler will automatically convert a box box point to a reference like &point.
This is another form of borrowing; in this case, the contents of the owned box
are being lent out.
Whenever a caller lends data to a callee, there are some limitations on what
the caller can do with the original. For example, if the contents of a