Potential name typo in borrowed pointer tutorial.

[nejucomo]

The following snippet confused me a bit. I believe "shape()" should be replaced with "select()" in the explanatory paragraph for the code snippet.

From commit 07edf90 tutorial-borrowed-ptr.md, line 674:

struct Point {x: float, y: float}; // as before

struct Size {w: float, h: float}; // as before

enum Shape {

Circle(Point, float), // origin, radius

Rectangle(Point, Size) // upper-left, dimensions

}

fn compute_area(shape: &Shape) -> float { 0f }

fn select(shape: &Shape, threshold: float,

a: &r/T, b: &r/T) -> &r/T {

if compute_area(shape) > threshold {a} else {b}

}

                                              // -+ r

fn select_based_on_unit_circle( // |-+ 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
is B, the function body. Both of the second two parameters `a` and `b`
share the same lifetime, `r`, which is a lifetime parameter of
`select_based_on_unit_circle()`. The caller will infer the
intersection of these two lifetimes as the lifetime of the returned
value, and hence the return value of `shape()` will be assigned a
lifetime of B. This will in turn lead to a compilation error, because
`select_based_on_unit_circle()` is supposed to return a value with the
lifetime `r`.

There is no function called "shape()", but "select()" would be consistent.

[nejucomo]

Ack! github formatting ate this, but the relevant text is unmunged at the bottom of the block quote.