rust

问题 I wanted to try implementing a trait generically and have users of the trait inherit this 'base' implementation automatically as long as they are compatible. This is the test-code I came up with (note that fmt::Show is std::fmt::Show ): trait Outspoken { fn speak(&self) -> String; } impl<T: fmt::Show> Outspoken for T { fn speak(&self) -> String { format!("{:?}", self) } } // In theory, we can now let my-types speak #[derive(Show)] struct MyType(i32); // 'Show' works assert_eq!(format!("{:?}",

问题 I need to refer to a value deep within a structure which includes an Option nested in a struct property, nested in a Result . My current (working) solution is: let raw = &packet[16..]; match PacketHeaders::from_ip_slice(raw) { Err(_value) => { /* ignore */ }, Ok(value) => { match value.ip { Some(Version4(header)) => { let key = format!("{}.{}.{}.{},{}.{}.{}.{}", header.source[0], header.source[1], header.source[2], header.source[3], header.destination[0], header.destination[1], header

问题 Why can't I push to this vector during inspect and do contains on it during skip_while ? I've implemented my own iterator for my own struct Chain like this: struct Chain { n: u32, } impl Chain { fn new(start: u32) -> Chain { Chain { n: start } } } impl Iterator for Chain { type Item = u32; fn next(&mut self) -> Option<u32> { self.n = digit_factorial_sum(self.n); Some(self.n) } } Now what I'd like to do it take while the iterator is producing unique values. So I'm inspect -ing the chain and

问题 I am working on a project where a dependency requires a specific nightly feature. I need to use this lib, but I am afraid that if I compile the project with nightly, I could depend on nother libraries that include another unstable feature dependency and I wouldn't be aware of that. Is it possible to compile the library that I need using nightly (while set the nightly version to version that already merged to the release branch) to some kind of "lib.a" file, and compile the whole project on

问题 I am working on a project where a dependency requires a specific nightly feature. I need to use this lib, but I am afraid that if I compile the project with nightly, I could depend on nother libraries that include another unstable feature dependency and I wouldn't be aware of that. Is it possible to compile the library that I need using nightly (while set the nightly version to version that already merged to the release branch) to some kind of "lib.a" file, and compile the whole project on

问题 I have a rubygem with a native extension written in rust. The native extension supports serializing its data-structure to JSON. However, whilst I've confirmed it's generating JSON, the string is always empty on the ruby side. Here's the ruby code: module RustCuckooFilter extend FFI::Library ffi_lib 'libcuckoofilter_cabi' class Instance < FFI::AutoPointer def export(path) RustCuckooFilter.export(self) end end attach_function :export, :rcf_cuckoofilter_export, [Instance], :pointer And the rust

问题 Take the following example (Playground): #![feature(generic_associated_types)] #![allow(incomplete_features)] trait Produce { type CustomError<'a>; fn produce<'a>(&'a self) -> Result<(), Self::CustomError<'a>>; } struct GenericProduce<T> { val: T, } struct GenericError<'a, T> { producer: &'a T, } impl<T> Produce for GenericProduce<T> { type CustomError<'a> = GenericError<'a, T>; fn produce<'a>(&'a self) -> Result<(), Self::CustomError<'a>> { Err(GenericError{producer: &self.val}) } } The

问题 Take the following example (Playground): #![feature(generic_associated_types)] #![allow(incomplete_features)] trait Produce { type CustomError<'a>; fn produce<'a>(&'a self) -> Result<(), Self::CustomError<'a>>; } struct GenericProduce<T> { val: T, } struct GenericError<'a, T> { producer: &'a T, } impl<T> Produce for GenericProduce<T> { type CustomError<'a> = GenericError<'a, T>; fn produce<'a>(&'a self) -> Result<(), Self::CustomError<'a>> { Err(GenericError{producer: &self.val}) } } The

问题 I want to have a child struct modify its parent struct. Example: // Problem: Having a struct's field modify the struct in which the field is. // MUST NOT be copyable nor clonable struct Updatee { value: u64, updater: Updater } impl Updatee { fn update(&mut self) { // ERROR: cannot borrow `*self` as mutable more than once at a time self.updater.update(self); } } // MUST NOT be copyable nor clonable struct Updater { value: u64 } impl Updater { fn update(&mut self, updatee: &mut Updatee) { self

问题 I want to have a child struct modify its parent struct. Example: // Problem: Having a struct's field modify the struct in which the field is. // MUST NOT be copyable nor clonable struct Updatee { value: u64, updater: Updater } impl Updatee { fn update(&mut self) { // ERROR: cannot borrow `*self` as mutable more than once at a time self.updater.update(self); } } // MUST NOT be copyable nor clonable struct Updater { value: u64 } impl Updater { fn update(&mut self, updatee: &mut Updatee) { self