Not only this, but match patterns are also extremely often used intentionally
to move values. The trivial example is something like
match some_opt_val {
Some(x) => do_something_with(x),
None => default_behavior()
}
By-ref matching is actually the more infrequent type of matching in my
e
What you're overlooking is that patterns are used for more than just
`match` expressions. They can also be used in both assignment statements
and in function/closure signatures. For example, note that `x` and `y` are
the same type in the following program:
fn main() {
let ref x = 3;
I think the 'ref' keyword removal is a very good idea. It has bitten
me several times, and the idea that pattern matching something
essentially performs a side effect (moving the value) leaves me
uncomfortable.
Cheers,
Emm
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I wonder if the idea of using ref by default in patterns for Copyless
types has being considered? The need to move on pattern match should
be infrequent. So it is better to use a special syntax for that case
skipping box ref and similar in most of the code.
On 28 May 2014 06:23, Corey Richardson
As with most things in Rust, in a pattern, a keyword means the
*opposite* of its normal meaning. So where `box e` in an expression
will box up the result of `e`, `box p` in a pattern will unbox `p`.
On Tue, May 27, 2014 at 9:50 AM, Tommi wrote:
> What is the meaning of this 'box ref foo' syntax f
What is the meaning of this 'box ref foo' syntax found in the tutorial over at
http://doc.rust-lang.org/tutorial.html#references
In short, it's:
enum Shape { Sphere(Box) }
let shape = Sphere(box 1.0f32);
let r = match shape {
Sphere(box ref radius) => *radius
};
I thought the 'box' keyword
