unit.rs - source
Description: Source of the Rust file `library/core/src/unit.rs`.

#
core/
unit.rs

    1/// Collapses all unit items from an iterator into one.
    2///
    3/// This is more useful when combined with higher-level abstractions, like
    4/// collecting to a `Result<(), E>` where you only care about errors:
    5///
    6/// ```
    7/// use std::io::*;
    8/// let data = vec![1, 2, 3, 4, 5];
    9/// let res: Result<()> = data.iter()
    10///     .map(|x| writeln!(stdout(), "{x}"))
    11///     .collect();
    12/// assert!(res.is_ok());
    13/// ```
    14#[stable(feature = "unit_from_iter", since = "1.23.0")]
    15impl FromIterator<()> for () {
    16    fn from_iter<I: IntoIterator<Item = ()>>(iter: I) -> Self {
    17        iter.into_iter().for_each(|()| {})
    18    }
    19}
    20
    21pub(crate) trait IsUnit {
    22    fn is_unit() -> bool;
    23}
    24
    25impl<T: ?Sized> IsUnit for T {
    26    default fn is_unit() -> bool {
    27        false
    28    }
    29}
    30
    31impl IsUnit for () {
    32    fn is_unit() -> bool {
    33        true
    34    }
    35}