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
experience.
-Kevin
On May 30, 2014, at 9:05 AM, Benjamin Striegel <ben.strie...@gmail.com> wrote:
> 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;
> let y = &3;
> foo(x);
> foo(y);
> }
>
> fn foo(x: &int) {
> println!("{:i}", *x);
> }
>
>
> Removing the `ref` keyword and making patterns reference by default would
> make `let x = 3;` declare a reference to an integer. Then you'd need a new
> keyword to express when you don't want this, and you're back at square one.
>
>
> On Fri, May 30, 2014 at 9:56 AM, Emmanuel Surleau
> <emmanuel.surl...@gmail.com> wrote:
> 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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