Enum Approximation 

pub enum Approximation<T, E> {
    Exact(T),
    Inexact(T, E),
}

Represent an calculation result with a possible error.

Variants

Exact(T)

The result is exact, contains the result value

Inexact(T, E)

The result is inexact, contains the result value and error

Implementations

impl<T, E> Approximation<T, E>

pub fn value(self) -> T

Get the value of the calculation regardless of error

pub const fn value_ref(&self) -> &T

Get a reference to the calculation result

pub fn value_with_exact(self) -> (T, bool)

The value together with whether the computation was exact.

The boolean is true for an exact result and false for an inexact one; the error E is discarded (use error when the error magnitude matters). Handy for the “value + exactness flag” pattern (e.g. MPFR’s exact flag, which a Ziv closure needs to report a zero radius for an exactly-representable result).

pub fn unwrap(self) -> T

Return the value if the result is exact, panic otherwise.

pub fn error(self) -> Option<E>

Return the error if the result is inexact, None if it is exact.

pub const fn error_ref(&self) -> Option<&E>

Borrow the error if the result is inexact, None if it is exact.

pub fn map<U, F>(self, f: F) -> Approximation<U, E>

where F: FnOnce(T) -> U,

Map the result value to a new type, preserving the error (if any).

pub fn and_then<U, F>(self, f: F) -> Approximation<U, E>

where F: FnOnce(T) -> Approximation<U, E>,

Chain a fallible mapping that itself returns an Approximation, combining the errors: an inexact input or an inexact result both yield an inexact result.

Trait Implementations

impl<T: Clone, E: Clone> Clone for Approximation<T, E>

fn clone(&self) -> Approximation<T, E>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Copy, E: Copy> Copy for Approximation<T, E>

impl<T: Debug, E: Debug> Debug for Approximation<T, E>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Eq, E: Eq> Eq for Approximation<T, E>

impl<T: PartialEq, E: PartialEq> PartialEq for Approximation<T, E>

fn eq(&self, other: &Approximation<T, E>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: PartialEq, E: PartialEq> StructuralPartialEq for Approximation<T, E>