The 'copy' parameter is the most generic way for the client to handle this situation.
-- Abhijeet Gaiha http://about.me/abhijeet.gaiha On Sunday, 2 June 2013 at 10:32 AM, Ziad Hatahet wrote: > 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 > (mailto:catamorph...@gmail.com)> wrote: > > On Sat, Jun 1, 2013 at 9:33 PM, Ziad Hatahet <hata...@gmail.com > > (mailto: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 > > _______________________________________________ > Rust-dev mailing list > Rust-dev@mozilla.org (mailto:Rust-dev@mozilla.org) > https://mail.mozilla.org/listinfo/rust-dev > >
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