Thanks everyone. I actually thought about the two suggestions before
posting. I thought there might be some common paradigm for this in the
language though.
So I take it that implementing a += operator overload function would not
have a generic way to handle the case where the same parameter is passed on
both sides?
--
Ziad
On Sat, Jun 1, 2013 at 9:42 PM, Tim Chevalier <catamorph...@gmail.com>wrote:
> On Sat, Jun 1, 2013 at 9:33 PM, Ziad Hatahet <hata...@gmail.com> wrote:
> > I have the following function:
> >
> > fn add_equal(x: &mut Complex, y: &Complex) {
> > x.real += y.real;
> > x.imag += y.imag;
> > }
> >
> > Calling the function with the same variable being passed to both
> arguments
> > (i.e. add_equal(&mut c, &c)), results in the compile error:
> >
> > error: cannot borrow `c` as immutable because it is also borrowed as
> mutable
> >
> > I am guessing this is to avoid aliasing issues? What is the way around
> this?
> >
>
> You can copy y instead of passing a reference to it:
> fn add_equal(x: &mut Complex, y: Complex) { ...
>
> Of course, that means that at the call site, you will have to write
> something like add_equal(&mut c, copy c).
>
> Unless you want to write a function that just takes one argument and
> doubles it, like Abhijeet suggested, I don't know of another way
> around this.
>
> Cheers,
> Tim
>
>
> --
> Tim Chevalier * http://catamorphism.org/ * Often in error, never in doubt
> "Not a riot, it's a rebellion." -- Boots Riley
> "Attention Bros and Trolls: When I call out your spew, I'm not angry,
> I'm defiant." -- Reg Braithwaite
>
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