Struct StrictlyPositive

pub struct StrictlyPositive;

Marker type enforcing that a value is strictly positive (greater than zero).

Use this type with Constrained<T, StrictlyPositive> to encode strict positivity at the type level.

You can construct a value constrained to be strictly positive using either the generic Constrained::new method or the convenient StrictlyPositive::new associated function.

Examples

use twine_core::constraint::{Constrained, StrictlyPositive};

// Generic constructor:
let x = Constrained::<_, StrictlyPositive>::new(1).unwrap();
assert_eq!(x.into_inner(), 1);

// Associated constructor:
let y = StrictlyPositive::new(3.14).unwrap();
assert_eq!(y.into_inner(), 3.14);

// Error cases:
assert!(StrictlyPositive::new(0).is_err());
assert!(StrictlyPositive::new(-1).is_err());
assert!(StrictlyPositive::new(f64::NAN).is_err());

Implementations

impl StrictlyPositive

pub fn new<T: PartialOrd + Zero>( value: T, ) -> Result<Constrained<T, StrictlyPositive>, ConstraintError>

Constructs a Constrained<T, StrictlyPositive> if the value is strictly positive.

Errors

Returns an error if the value is zero, negative, or not a number (NaN).

Trait Implementations

impl Clone for StrictlyPositive

fn clone(&self) -> StrictlyPositive

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: PartialOrd + Zero> Constraint<T> for StrictlyPositive

fn check(value: &T) -> Result<(), ConstraintError>

Checks that the given value satisfies this constraint.

impl Debug for StrictlyPositive

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

Formats the value using the given formatter.

impl PartialEq for StrictlyPositive

fn eq(&self, other: &StrictlyPositive) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for StrictlyPositive

impl Eq for StrictlyPositive

impl StructuralPartialEq for StrictlyPositive