rust

问题 I am studying Rust by Example and running code from the "Alias" page: struct Point { x: i32, y: i32, z: i32, } fn main() { let mut point = Point { x: 0, y: 0, z: 0 }; { let borrowed_point = &point; let another_borrow = &point; // Data can be accessed via the references and the original owner println!( "Point has coordinates: ({}, {}, {})", borrowed_point.x, another_borrow.y, point.z ); // Error! Can't borrow point as mutable because it's currently // borrowed as immutable. let mutable_borrow

问题 I am studying Rust by Example and running code from the "Alias" page: struct Point { x: i32, y: i32, z: i32, } fn main() { let mut point = Point { x: 0, y: 0, z: 0 }; { let borrowed_point = &point; let another_borrow = &point; // Data can be accessed via the references and the original owner println!( "Point has coordinates: ({}, {}, {})", borrowed_point.x, another_borrow.y, point.z ); // Error! Can't borrow point as mutable because it's currently // borrowed as immutable. let mutable_borrow

问题 Right now I have code that uses the rusqlite sqlite bindings to open a db connection and do a bunch of db operations in my application like this: extern crate rusqlite; use rusqlite::SqliteConnection; struct MyAppState { db: SqliteConnection, // ... pretend there's other fields here ... } impl MyAppState { fn new() -> MyAppState { let db = SqliteConnection::open(":memory:").unwrap(); MyAppState { db: db } } fn query_some_info(&mut self, arg: i64) -> i64 { let mut stmt = self.db.prepare(

问题 Right now I have code that uses the rusqlite sqlite bindings to open a db connection and do a bunch of db operations in my application like this: extern crate rusqlite; use rusqlite::SqliteConnection; struct MyAppState { db: SqliteConnection, // ... pretend there's other fields here ... } impl MyAppState { fn new() -> MyAppState { let db = SqliteConnection::open(":memory:").unwrap(); MyAppState { db: db } } fn query_some_info(&mut self, arg: i64) -> i64 { let mut stmt = self.db.prepare(

问题 I have a simple web server using Warp that serves static files. I followed the examples in the Warp docs to get the following: let index_html = warp::path("index.html").map(handlers::index_html); // reply is handled in `handlers::` let script_js = warp::path("script.js").map(handlers::script_js); let routes = warp::get().and(index_html.or(script_js)); warp::serve(routes).run(([127, 0, 0, 1], 8000)).await; This returns files when requested from localhost:8000/index.html and localhost:8000

问题 I have a simple web server using Warp that serves static files. I followed the examples in the Warp docs to get the following: let index_html = warp::path("index.html").map(handlers::index_html); // reply is handled in `handlers::` let script_js = warp::path("script.js").map(handlers::script_js); let routes = warp::get().and(index_html.or(script_js)); warp::serve(routes).run(([127, 0, 0, 1], 8000)).await; This returns files when requested from localhost:8000/index.html and localhost:8000

问题 I have a simple web server using Warp that serves static files. I followed the examples in the Warp docs to get the following: let index_html = warp::path("index.html").map(handlers::index_html); // reply is handled in `handlers::` let script_js = warp::path("script.js").map(handlers::script_js); let routes = warp::get().and(index_html.or(script_js)); warp::serve(routes).run(([127, 0, 0, 1], 8000)).await; This returns files when requested from localhost:8000/index.html and localhost:8000

问题 I'm trying to insert CSV data into a SQLite database. stripe_id is optional, and so its type is Option<&str> . All the other fields are &str . When I use conn.execute to insert the values, they all insert correctly except for stripe_id , which throws an error saying it expects &str and not Option . I've searched the docs and Option<T> implements ToSQL , and when I've tried replacing my code with the Rusqlite example that includes an Option value, it throws the same error for the example code.

问题 Rust's std::process::Command allows configuring the process' stdin via the stdin method, but it appears that that method only accepts existing files or pipes. Given a slice of bytes, how would you go about writing it to the stdin of a Command ? 回答1: You can create a stdin pipe and write the bytes on it. As Command::output immediately closes the stdin, you'll have to use Command::spawn . Command::spawn inherits stdin by default. You'll have to use Command::stdin to change the behavior. Here is

问题 Rust's std::process::Command allows configuring the process' stdin via the stdin method, but it appears that that method only accepts existing files or pipes. Given a slice of bytes, how would you go about writing it to the stdin of a Command ? 回答1: You can create a stdin pipe and write the bytes on it. As Command::output immediately closes the stdin, you'll have to use Command::spawn . Command::spawn inherits stdin by default. You'll have to use Command::stdin to change the behavior. Here is