newtype-tools 1.0.13

A lightweight library designed to make the newtype idiom more ergonomic to use.
Documentation 
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#![cfg(feature = "derive")]

const EXPECTED_WEIGHT: u64 = 0;

#[test]
fn sub() {
    #[derive(Debug, newtype_tools::Newtype)]
    /// Doc comment.
    #[newtype(sub(
        Oranges,
        output = "Weight",
        with = "|apples, oranges| Weight(apples.0 - oranges.0 as u64 * 2)"
    ))]
    struct Apples(u64);
    #[derive(Debug)]
    struct Oranges(u32);
    #[derive(Debug, PartialEq)]
    struct Weight(u64);

    let res = Apples(42) - Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = &Apples(42) - Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = Apples(42) - &Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = &Apples(42) - &Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
}

#[test]
fn generic_sub() {
    #[derive(Debug, newtype_tools::Newtype)]
    #[newtype(sub(
        Oranges,
        output = "Weight",
        with = "|apples, oranges| Weight(apples.0.clone() - oranges.0 as u64 * 2)"
    ))]
    struct Apples<T>(T)
    where
        T: core::ops::Sub<u64, Output = u64> + Clone;
    #[derive(Debug)]
    struct Oranges(u32);
    #[derive(Debug, PartialEq)]
    struct Weight(u64);

    let res = Apples(42) - Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = &Apples(42) - Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = Apples(42) - &Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
    let res = &Apples(42) - &Oranges(21);
    assert_eq!(res, Weight(EXPECTED_WEIGHT));
}
#[test]
fn sub_assign() {
    #[derive(Debug, newtype_tools::Newtype, PartialEq)]
    /// Doc comment.
    #[newtype(sub_assign(Oranges, with = "|apples, oranges| apples.0 -= oranges.0 as u64 * 2"))]
    struct Apples(u64);
    #[derive(Debug, PartialEq)]
    struct Oranges(u32);

    let mut apples = Apples(42);
    apples -= Oranges(21);
    assert_eq!(apples, Apples(EXPECTED_WEIGHT));
    let mut apples = Apples(42);
    apples -= &Oranges(21);
    assert_eq!(apples, Apples(EXPECTED_WEIGHT));
}

#[test]
fn generic_sub_assign() {
    #[derive(Debug, newtype_tools::Newtype, PartialEq)]
    #[newtype(sub_assign(Oranges, with = "|apples, oranges| apples.0 -= oranges.0 as u64 * 2"))]
    struct Apples<T>(T)
    where
        T: core::ops::SubAssign<u64> + Clone;
    #[derive(Debug, PartialEq)]
    struct Oranges(u32);

    let mut apples = Apples(42);
    let oranges = Oranges(21);
    apples -= oranges;
    assert_eq!(apples, Apples(EXPECTED_WEIGHT));
    let mut apples = Apples(42);
    let oranges = Oranges(21);
    apples -= &oranges;
    assert_eq!(apples, Apples(EXPECTED_WEIGHT));
    assert_eq!(oranges, Oranges(21));
}