Crate option_operations

Expand description

option-operations provides traits and auto-implementations to improve arithmetic operations usability when dealing with Options.

§Example

Dealing with two Options, can lead to verbose expressions:

let lhs = Some(1u64);
let rhs = Some(u64::MAX);

assert_eq!(
    lhs.zip(rhs).map(|(lhs, rhs)| lhs.saturating_add(rhs)),
    Some(u64::MAX),
);

Thanks to the trait OptionSaturatingAdd we can write:

assert_eq!(
    lhs.opt_saturating_add(rhs),
    Some(u64::MAX),
);

The trait can also be used with the inner type:

assert_eq!(
    lhs.opt_saturating_add(u64::MAX),
    Some(u64::MAX),
);

assert_eq!(
    1.opt_saturating_add(rhs),
    Some(u64::MAX),
);

§Alternative to `PartialOrd` for `Option<T>`

Another purpose is to workaround the PartiaOrd implementation for Option<T>, which uses the declaration order of the variants for Option. None appearing before Some(_), it results in the following behavior:

let some_0 = Some(0);
let none: Option<u64> = None;

assert_eq!(none.partial_cmp(&some_0), Some(Ordering::Less));
assert_eq!(some_0.partial_cmp(&none), Some(Ordering::Greater));

In some cases, we might consider that None reflects a value which is not defined and thus can not be compared with Some(_).

assert_eq!(none.opt_cmp(&some_0), None);
assert_eq!(some_0.opt_cmp(&none), None);

Of course, this is consistent with other usual comparisons:

assert_eq!(none.opt_lt(&some_0), None);
assert_eq!(none.opt_min(some_0), None);

Re-exports§

pub use add::OptionAdd;
pub use add::OptionAddAssign;
pub use add::OptionCheckedAdd;
pub use add::OptionOverflowingAdd;
pub use add::OptionSaturatingAdd;
pub use add::OptionWrappingAdd;
pub use error::Error;
pub use div::OptionCheckedDiv;
pub use div::OptionDiv;
pub use div::OptionDivAssign;
pub use div::OptionOverflowingDiv;
pub use div::OptionWrappingDiv;
pub use eq::OptionEq;
pub use min_max::OptionMinMax;
pub use mul::OptionCheckedMul;
pub use mul::OptionMul;
pub use mul::OptionMulAssign;
pub use mul::OptionOverflowingMul;
pub use mul::OptionSaturatingMul;
pub use mul::OptionWrappingMul;
pub use ord::OptionOrd;
pub use rem::OptionCheckedRem;
pub use rem::OptionOverflowingRem;
pub use rem::OptionRem;
pub use rem::OptionRemAssign;
pub use rem::OptionWrappingRem;
pub use sub::OptionCheckedSub;
pub use sub::OptionOverflowingSub;
pub use sub::OptionSaturatingSub;
pub use sub::OptionSub;
pub use sub::OptionSubAssign;
pub use sub::OptionWrappingSub;

Modules§

add: Traits for the addition OptionOperations.
div: Traits for the division OptionOperations.
eq: Trait for the equality OptionOperations.
error: Error type which can be returned by some OptionOperations.
min_max: Traits for the minimun and maximum OptionOperations.
mul: Traits for the multiplication OptionOperations.
ord: Trait for the order OptionOperations.
prelude
rem: Traits for the remainder OptionOperations.
sub: Traits for the substraction OptionOperations.

Traits§

OptionOperations: Trait for inner types participating in option-operations.