On Wed, May 29, 2013 at 1:53 PM, Ziad Hatahet <hata...@gmail.com> wrote: > Hi all, > > Does using Option incur a runtime cost (like increased memory usage) > compared to a hypothetical case if Rust had a NULL type in the language? Or > does it get optimized away, such that it is akin to using NULL in the first > place (albeit safer of course)? > > I have not looked at any assemblies, ut my intuition says that a comparison > with None is a single-word check, so it should be pretty fast. > > Thanks > > -- > Ziad
Any enum with a non-nullable pointer type (~T, @T, &T, ~[T], @[T], ~str, @str) and second zero-size variant is optimized to a nullable pointer now. The optimization still needs to be extended to slices though (they're two words, but the enum could also be 2 words, not 3). _______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
