Trait Add

1.0.0 (const: unstable) · Source

pub trait Add<Rhs = Self> {
    type Output;

    // Required method
    const fn add(self, rhs: Rhs) -> Self::Output;
}

Expand description

The addition operator +.

Note that Rhs is Self by default, but this is not mandatory. For example, std::time::SystemTime implements Add<Duration>, which permits operations of the form SystemTime = SystemTime + Duration.

§Examples

§`Add`able points

use std::ops::Add;

#[derive(Debug, Copy, Clone, PartialEq)]
struct Point {
    x: i32,
    y: i32,
}

impl Add for Point {
    type Output = Self;

    fn add(self, other: Self) -> Self {
        Self {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
           Point { x: 3, y: 3 });

§Implementing `Add` with generics

Here is an example of the same Point struct implementing the Add trait using generics.

use std::ops::Add;

#[derive(Debug, Copy, Clone, PartialEq)]
struct Point<T> {
    x: T,
    y: T,
}

// Notice that the implementation uses the associated type `Output`.
impl<T: Add<Output = T>> Add for Point<T> {
    type Output = Self;

    fn add(self, other: Self) -> Self::Output {
        Self {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
           Point { x: 3, y: 3 });

Required Associated Types§

1.0.0 · Source

type Output

The resulting type after applying the + operator.

Required Methods§

1.0.0 · Source

const fn add(self, rhs: Rhs) -> Self::Output

Performs the + operation.

§Example

assert_eq!(12 + 1, 13);

Implementors§

Source §

impl Add for Expr

This consumes the String on the left-hand side and re-uses its buffer (growing it if necessary). This is done to avoid allocating a new String and copying the entire contents on every operation, which would lead to O(n^2) running time when building an n-byte string by repeated concatenation.

The string on the right-hand side is only borrowed; its contents are copied into the returned String.

§Examples

Concatenating two Strings takes the first by value and borrows the second:

let a = String::from("hello");
let b = String::from(" world");
let c = a + &b;
// `a` is moved and can no longer be used here.

If you want to keep using the first String, you can clone it and append to the clone instead:

let a = String::from("hello");
let b = String::from(" world");
let c = a.clone() + &b;
// `a` is still valid here.

Concatenating &str slices can be done by converting the first to a String:

let a = "hello";
let b = " world";
let c = a.to_string() + b;

Source §

impl Add<Duration> for NaiveDateTime

Add std::time::Duration to NaiveDateTime.

As a part of Chrono’s [leap second handling], the addition assumes that there is no leap second ever, except when the NaiveDateTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

§Panics

The result will be clamped to valid days in the resulting month, see checked_add_months for details.

§Panics

Panics if the resulting date would be out of range. Consider using NaiveDate::checked_add_months to get an Option instead.

§Example

use chrono::{Months, NaiveDate};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

assert_eq!(from_ymd(2014, 1, 1) + Months::new(1), from_ymd(2014, 2, 1));
assert_eq!(from_ymd(2014, 1, 1) + Months::new(11), from_ymd(2014, 12, 1));
assert_eq!(from_ymd(2014, 1, 1) + Months::new(12), from_ymd(2015, 1, 1));
assert_eq!(from_ymd(2014, 1, 1) + Months::new(13), from_ymd(2015, 2, 1));
assert_eq!(from_ymd(2014, 1, 31) + Months::new(1), from_ymd(2014, 2, 28));
assert_eq!(from_ymd(2020, 1, 31) + Months::new(1), from_ymd(2020, 2, 29));

§Panics

Panics if the resulting date would be out of range. Consider using NaiveDate::checked_add_signed to get an Option instead.

§Example

use chrono::{NaiveDate, TimeDelta};

let from_ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();

assert_eq!(from_ymd(2014, 1, 1) + TimeDelta::zero(), from_ymd(2014, 1, 1));
assert_eq!(from_ymd(2014, 1, 1) + TimeDelta::try_seconds(86399).unwrap(), from_ymd(2014, 1, 1));
assert_eq!(
    from_ymd(2014, 1, 1) + TimeDelta::try_seconds(-86399).unwrap(),
    from_ymd(2014, 1, 1)
);
assert_eq!(from_ymd(2014, 1, 1) + TimeDelta::try_days(1).unwrap(), from_ymd(2014, 1, 2));
assert_eq!(from_ymd(2014, 1, 1) + TimeDelta::try_days(-1).unwrap(), from_ymd(2013, 12, 31));
assert_eq!(from_ymd(2014, 1, 1) + TimeDelta::try_days(364).unwrap(), from_ymd(2014, 12, 31));
assert_eq!(
    from_ymd(2014, 1, 1) + TimeDelta::try_days(365 * 4 + 1).unwrap(),
    from_ymd(2018, 1, 1)
);
assert_eq!(
    from_ymd(2014, 1, 1) + TimeDelta::try_days(365 * 400 + 97).unwrap(),
    from_ymd(2414, 1, 1)
);

impl Add<TimeDelta> for NaiveTime

Add TimeDelta to NaiveTime.

This wraps around and never overflows or underflows. In particular the addition ignores integral number of days.

As a part of Chrono’s leap second handling, the addition assumes that there is no leap second ever, except when the NaiveTime itself represents a leap second in which case the assumption becomes that there is exactly a single leap second ever.

§Example

use chrono::{NaiveTime, TimeDelta};

let from_hmsm = |h, m, s, milli| NaiveTime::from_hms_milli_opt(h, m, s, milli).unwrap();

assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::zero(), from_hmsm(3, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(1).unwrap(), from_hmsm(3, 5, 8, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(-1).unwrap(), from_hmsm(3, 5, 6, 0));
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(60 + 4).unwrap(),
    from_hmsm(3, 6, 11, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(7 * 60 * 60 - 6 * 60).unwrap(),
    from_hmsm(9, 59, 7, 0)
);
assert_eq!(
    from_hmsm(3, 5, 7, 0) + TimeDelta::try_milliseconds(80).unwrap(),
    from_hmsm(3, 5, 7, 80)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) + TimeDelta::try_milliseconds(280).unwrap(),
    from_hmsm(3, 5, 8, 230)
);
assert_eq!(
    from_hmsm(3, 5, 7, 950) + TimeDelta::try_milliseconds(-980).unwrap(),
    from_hmsm(3, 5, 6, 970)
);

The addition wraps around.

assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(22*60*60).unwrap(), from_hmsm(1, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_seconds(-8*60*60).unwrap(), from_hmsm(19, 5, 7, 0));
assert_eq!(from_hmsm(3, 5, 7, 0) + TimeDelta::try_days(800).unwrap(), from_hmsm(3, 5, 7, 0));

Leap seconds are handled, but the addition assumes that it is the only leap second happened.

let leap = from_hmsm(3, 5, 59, 1_300);
assert_eq!(leap + TimeDelta::zero(), from_hmsm(3, 5, 59, 1_300));
assert_eq!(leap + TimeDelta::try_milliseconds(-500).unwrap(), from_hmsm(3, 5, 59, 800));
assert_eq!(leap + TimeDelta::try_milliseconds(500).unwrap(), from_hmsm(3, 5, 59, 1_800));
assert_eq!(leap + TimeDelta::try_milliseconds(800).unwrap(), from_hmsm(3, 6, 0, 100));
assert_eq!(leap + TimeDelta::try_seconds(10).unwrap(), from_hmsm(3, 6, 9, 300));
assert_eq!(leap + TimeDelta::try_seconds(-10).unwrap(), from_hmsm(3, 5, 50, 300));
assert_eq!(leap + TimeDelta::try_days(1).unwrap(), from_hmsm(3, 5, 59, 300));

Source §

impl Add<B0> for UTerm

UTerm + B0 = UTerm

Source §

type Output = UTerm

Source §

impl Add<B1> for UTerm

UTerm + B1 = UInt<UTerm, B1>

Z0 + I = I

impl<Tz> Add<Days> for DateTime<Tz>
where Tz: TimeZone,

Add Days to NaiveDateTime.

§Panics

Panics if:

The resulting date would be out of range.
The local time at the resulting date does not exist or is ambiguous, for example during a daylight saving time transition.

Strongly consider using DateTime<Tz>::checked_add_days to get an Option instead.

Source §

type Output = DateTime<Tz>

Source §

impl<Tz> Add<FixedOffset> for DateTime<Tz>
where Tz: TimeZone,

Add FixedOffset to the datetime value of DateTime (offset remains unchanged).

§Panics

Panics if the resulting date would be out of range.

Source §

type Output = DateTime<Tz>

Source §

impl<Tz> Add<TimeDelta> for Date<Tz>
where Tz: TimeZone,

Source §

type Output = Date<Tz>

Source §

impl<Tz> Add<TimeDelta> for DateTime<Tz>
where Tz: TimeZone,

Add TimeDelta to DateTime.

Source §

Trait AddCopy item path

§Examples

§Addable points

§Implementing Add with generics

Required Associated Types§

type Output

Required Methods§

const fn add(self, rhs: Rhs) -> Self::Output

§Example

Implementors§

impl Add for Expr

type Output = Expr

impl Add for f16

type Output = f16

impl Add for f32

type Output = f32

impl Add for f64

type Output = f64

impl Add for f128

type Output = f128

impl Add for i8

type Output = i8

impl Add for i16

type Output = i16

impl Add for i32

type Output = i32

impl Add for i64

type Output = i64

impl Add for i128

type Output = i128

impl Add for isize

type Output = isize

impl Add for u8

type Output = u8

impl Add for u16

type Output = u16

impl Add for u32

type Output = u32

impl Add for u64

type Output = u64

impl Add for u128

type Output = u128

impl Add for usize

type Output = usize

impl Add for IntervalDayTime

type Output = IntervalDayTime

impl Add for IntervalMonthDayNano

type Output = IntervalMonthDayNano

impl Add for i256

type Output = i256

impl Add for Assume

type Output = Assume

impl Add for Saturating<i8>

type Output = Saturating<i8>

impl Add for Saturating<i16>

type Output = Saturating<i16>

impl Add for Saturating<i32>

type Output = Saturating<i32>

impl Add for Saturating<i64>

type Output = Saturating<i64>

impl Add for Saturating<i128>

type Output = Saturating<i128>

impl Add for Saturating<isize>

type Output = Saturating<isize>

impl Add for Saturating<u8>

type Output = Saturating<u8>

impl Add for Saturating<u16>

type Output = Saturating<u16>

impl Add for Saturating<u32>

type Output = Saturating<u32>

impl Add for Saturating<u64>

type Output = Saturating<u64>

impl Add for Saturating<u128>

type Output = Saturating<u128>

impl Add for Saturating<usize>

type Output = Saturating<usize>

impl Add for Wrapping<i8>

type Output = Wrapping<i8>

impl Add for Wrapping<i16>

type Output = Wrapping<i16>

Trait Add

§`Add`able points

§Implementing `Add` with generics