Trait OptionCheckedSub 

pub trait OptionCheckedSub<Rhs = Self, InnerRhs = Rhs> {
    type Output;

    // Required method
    fn opt_checked_sub(self, rhs: Rhs) -> Result<Option<Self::Output>, Error>;
}

Trait for values and Options checked substraction.

Implementing this trait leads to the following auto-implementations:

• OptionCheckedSub<Option<InnerRhs>> for T.
• OptionCheckedSub<Rhs> for Option<T>.
• OptionCheckedSub<Option<InnerRhs>> for Option<T>.
• … and some variants with references.

Note that since the std library doesn’t define any CheckedSub trait, users must provide the base implementation for the inner type.

Required Associated Types

type Output

The resulting inner type after applying the substraction.

Required Methods

fn opt_checked_sub(self, rhs: Rhs) -> Result<Option<Self::Output>, Error>

Computes the checked substraction.

• Returns Ok(Some(result)) if result could be computed.
• Returns Ok(None) if at least one argument is None.
• Returns Err(Error::Overflow) if an overflow occured.

Implementations on Foreign Types

impl OptionCheckedSub for i8

type Output = i8

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for i16

type Output = i16

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for i32

type Output = i32

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for i64

type Output = i64

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for i128

type Output = i128

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for u8

type Output = u8

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for u16

type Output = u16

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for u32

type Output = u32

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for u64

type Output = u64

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for u128

type Output = u128

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub for Duration

type Output = Duration

fn opt_checked_sub(self, rhs: Self) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub<Duration> for Instant

Available on crate feature std only.

type Output = Instant

fn opt_checked_sub(self, rhs: Duration) -> Result<Option<Self::Output>, Error>

impl OptionCheckedSub<Duration> for SystemTime

Available on crate feature std only.

type Output = SystemTime

fn opt_checked_sub(self, rhs: Duration) -> Result<Option<Self::Output>, Error>

impl<T, InnerRhs> OptionCheckedSub<&Option<InnerRhs>, InnerRhs> for Option<T>

where T: OptionOperations + OptionCheckedSub<InnerRhs>, InnerRhs: Copy,

type Output = <T as OptionCheckedSub<InnerRhs>>::Output

fn opt_checked_sub( self, rhs: &Option<InnerRhs>, ) -> Result<Option<Self::Output>, Error>

impl<T, InnerRhs> OptionCheckedSub<Option<InnerRhs>, InnerRhs> for Option<T>

where T: OptionOperations + OptionCheckedSub<InnerRhs>,

type Output = <T as OptionCheckedSub<InnerRhs>>::Output

fn opt_checked_sub( self, rhs: Option<InnerRhs>, ) -> Result<Option<Self::Output>, Error>

impl<T, Rhs> OptionCheckedSub<Rhs> for Option<T>

where T: OptionOperations + OptionCheckedSub<Rhs>,

type Output = <T as OptionCheckedSub<Rhs>>::Output

fn opt_checked_sub(self, rhs: Rhs) -> Result<Option<Self::Output>, Error>

Implementors

impl<T, InnerRhs> OptionCheckedSub<&Option<InnerRhs>, InnerRhs> for T

where T: OptionOperations + OptionCheckedSub<InnerRhs>, InnerRhs: Copy,

type Output = <T as OptionCheckedSub<InnerRhs>>::Output

impl<T, InnerRhs> OptionCheckedSub<Option<InnerRhs>, InnerRhs> for T

where T: OptionOperations + OptionCheckedSub<InnerRhs>,

type Output = <T as OptionCheckedSub<InnerRhs>>::Output