Result Combinators

pub trait ResultExt<T, E> {    fn map_err_into<U: From<E>>(self) -> Result<T, U>;        fn or_else_ok<F>(self, f: F) -> Result<T, E>    where        F: FnOnce(E) -> T;        fn and_then_async<F, Fut, U, E2>(self, f: F) -> impl std::future::Future<Output = Result<U, E2>>    where        F: FnOnce(T) -> Fut,        Fut: std::future::Future<Output = Result<U, E2>>,        E: Into<E2>;}impl<T, E> ResultExt<T, E> for Result<T, E> {    fn map_err_into<U: From<E>>(self) -> Result<T, U> {        self.map_err(Into::into)    }        fn or_else_ok<F>(self, f: F) -> Result<T, E>    where        F: FnOnce(E) -> T,    {        self.or_else(|e| Ok(f(e)))    }        fn and_then_async<F, Fut, U, E2>(self, f: F) -> impl std::future::Future<Output = Result<U, E2>>    where        F: FnOnce(T) -> Fut,        Fut: std::future::Future<Output = Result<U, E2>>,        E: Into<E2>,    {        async move {            match self {                Ok(val) => f(val).await,                Err(e) => Err(e.into()),            }        }    }}pub fn combine_results<T, E>(results: Vec<Result<T, E>>) -> Result<Vec<T>, Vec<E>> {    let mut values = Vec::new();    let mut errors = Vec::new();        for result in results {        match result {            Ok(val) => values.push(val),            Err(e) => errors.push(e),        }    }        if errors.is_empty() {        Ok(values)    } else {        Err(errors)    }}

use result_combinators::{ResultExt, combine_results};// Error conversionlet res: Result<i32, String> = Err("error".to_string());let converted: Result<i32, Box<dyn std::error::Error>> = res.map_err_into();// Fallback valuelet value = res.or_else_ok(|_| 0);// Combine multiple resultslet results = vec![Ok(1), Ok(2), Err("error".to_string())];let combined = combine_results(results);