System Initiative

/// Extensions to [`Result`]. /// /// Provides behavior currently unstable: /// - `result_option_inspect` [#91345](https://github.com/rust-lang/rust/issues/91345) pub trait ResultExt<T, E> { /// Calls the provided closure with a reference to the contained value (if [`Ok`]). /// /// # Examples /// /// ```` /// # use si_std::ResultExt; /// let x: u8 = "4" /// .parse::<u8>() /// .si_inspect(|x| println!("original: {x}")) /// .map(|x| x.pow(3)) /// .expect("failed to parse number"); /// ```` fn si_inspect<F: FnOnce(&T)>(self, f: F) -> Self; /// Calls the provided closure with a reference to the contained error (if [`Err`]). /// /// # Examples /// /// ``` /// # use si_std::ResultExt; /// use std::{fs, io}; /// /// fn read() -> io::Result<String> { /// fs::read_to_string("address.txt") /// .si_inspect_err(|e| eprintln!("failed to read file: {e}")) /// } /// ``` fn si_inspect_err<F: FnOnce(&E)>(self, f: F) -> Self; } impl<T, E> ResultExt<T, E> for Result<T, E> { fn si_inspect<F: FnOnce(&T)>(self, f: F) -> Self { if let Ok(ref t) = self { f(t) } self } fn si_inspect_err<F: FnOnce(&E)>(self, f: F) -> Self { if let Err(ref e) = self { f(e); } self } }