Trait StepFns

pub trait StepFns<T> {
    // Required methods
    fn add_one(start: &T) -> T;
    fn sub_one(start: &T) -> T;
}

Successor and predecessor functions defined for T, but as free functions rather than methods on T itself.

This is useful as a workaround for Rust’s “orphan rules”, which prevent you from implementing StepLite for T if T is a foreign type.

NOTE: This will likely be deprecated and then eventually removed once the standard library’s Step trait is stabilised, as most crates will then likely implement Step for their types where appropriate.

See this issue for details about that stabilization process.

There is also a blanket implementation of StepFns for all types implementing StepLite. Consumers of this crate should prefer to implement StepLite for their own types, and only fall back to StepFns when dealing with foreign types.

Required Methods

fn add_one(start: &T) -> T

Returns the successor of value start.

If this would overflow the range of values supported by Self, this function is allowed to panic, wrap, or saturate. The suggested behavior is to panic when debug assertions are enabled, and to wrap or saturate otherwise.

fn sub_one(start: &T) -> T

Returns the predecessor of value start.

If this would overflow the range of values supported by Self, this function is allowed to panic, wrap, or saturate. The suggested behavior is to panic when debug assertions are enabled, and to wrap or saturate otherwise.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> StepFns<T> for T

where T: StepLite,