Trait Map

pub trait Map<O, E>: Sized {
    // Required methods
    fn map_ok<F, O2>(self, _: F) -> MapOk<Self, F> 
       where F: FnMut(O) -> O2;
    fn map_err<F, E2>(self, _: F) -> MapErr<Self, F> 
       where F: FnMut(E) -> E2;
}

Extension trait for Iterator<Item = Result<O, E>> to selectively transform Oks and Errors.

Required Methods

fn map_ok<F, O2>(self, _: F) -> MapOk<Self, F>

where F: FnMut(O) -> O2,

Map all Ok items while leaving Err as is

use resiter::map::Map;
use std::str::FromStr;

let mapped: Vec<_> = ["1", "2", "a", "4", "5"]
    .iter()
    .map(|txt| usize::from_str(txt))
    .map_ok(|i| 2 * i)
    .collect();

assert_eq!(mapped[0], Ok(2));
assert_eq!(mapped[1], Ok(4));
assert!(mapped[2].is_err());
assert_eq!(mapped[3], Ok(8));
assert_eq!(mapped[4], Ok(10));

fn map_err<F, E2>(self, _: F) -> MapErr<Self, F>

where F: FnMut(E) -> E2,

Map all Err items while leaving Ok as is

use resiter::map::Map;
use std::str::FromStr;
let mapped: Vec<_> = ["1", "2", "a", "4", "5"]
    .iter()
    .map(|txt| usize::from_str(txt))
    .map_err(|e| format!("{:?}", e))
    .collect();

assert_eq!(
    mapped,
    vec![
        Ok(1),
        Ok(2),
        Err("ParseIntError { kind: InvalidDigit }".to_string()),
        Ok(4),
        Ok(5),
    ]
);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<I, O, E> Map<O, E> for I

where I: Iterator<Item = Result<O, E>> + Sized,