diff options
Diffstat (limited to 'doc/tutorial-borrowed-ptr.md')
| -rw-r--r-- | doc/tutorial-borrowed-ptr.md | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/doc/tutorial-borrowed-ptr.md b/doc/tutorial-borrowed-ptr.md index e638579253f..8e0ca297f65 100644 --- a/doc/tutorial-borrowed-ptr.md +++ b/doc/tutorial-borrowed-ptr.md @@ -486,12 +486,12 @@ For example, we could write a subroutine like this: ~~~ struct Point {x: float, y: float} -fn get_x(p: &r/Point) -> &r/float { &p.x } +fn get_x(p: &'r Point) -> &'r float { &p.x } ~~~ Here, the function `get_x()` returns a pointer into the structure it -was given. The type of the parameter (`&r/Point`) and return type -(`&r/float`) both use a new syntactic form that we have not seen so +was given. The type of the parameter (`&'r Point`) and return type +(`&'r float`) both use a new syntactic form that we have not seen so far. Here the identifier `r` names the lifetime of the pointer explicitly. So in effect, this function declares that it takes a pointer with lifetime `r` and returns a pointer with that same @@ -572,8 +572,8 @@ function: # Rectangle(Point, Size) // upper-left, dimensions # } # fn compute_area(shape: &Shape) -> float { 0f } -fn select<T>(shape: &r/Shape, threshold: float, - a: &r/T, b: &r/T) -> &r/T { +fn select<T>(shape: &'r Shape, threshold: float, + a: &'r T, b: &'r T) -> &'r T { if compute_area(shape) > threshold {a} else {b} } ~~~ @@ -593,17 +593,17 @@ example: # } # fn compute_area(shape: &Shape) -> float { 0f } # fn select<T>(shape: &Shape, threshold: float, -# a: &r/T, b: &r/T) -> &r/T { +# a: &'r T, b: &'r T) -> &'r T { # if compute_area(shape) > threshold {a} else {b} # } - // -+ r -fn select_based_on_unit_circle<T>( // |-+ B - threshold: float, a: &r/T, b: &r/T) -> &r/T { // | | - // | | - let shape = Circle(Point {x: 0., y: 0.}, 1.); // | | - select(&shape, threshold, a, b) // | | -} // |-+ - // -+ + // -+ r +fn select_based_on_unit_circle<T>( // |-+ B + threshold: float, a: &'r T, b: &'r T) -> &'r T { // | | + // | | + let shape = Circle(Point {x: 0., y: 0.}, 1.); // | | + select(&shape, threshold, a, b) // | | +} // |-+ + // -+ ~~~ In this call to `select()`, the lifetime of the first parameter shape @@ -629,8 +629,8 @@ returned. Here is how the new `select()` might look: # Rectangle(Point, Size) // upper-left, dimensions # } # fn compute_area(shape: &Shape) -> float { 0f } -fn select<T>(shape: &tmp/Shape, threshold: float, - a: &r/T, b: &r/T) -> &r/T { +fn select<T>(shape: &'tmp Shape, threshold: float, + a: &'r T, b: &'r T) -> &'r T { if compute_area(shape) > threshold {a} else {b} } ~~~ @@ -649,7 +649,7 @@ concise to just omit the named lifetime for `shape` altogether: # } # fn compute_area(shape: &Shape) -> float { 0f } fn select<T>(shape: &Shape, threshold: float, - a: &r/T, b: &r/T) -> &r/T { + a: &'r T, b: &'r T) -> &'r T { if compute_area(shape) > threshold {a} else {b} } ~~~ |