Macro nonneg 

macro_rules! nonneg {
    ($t:ty) => { ... };
    ($val:expr) => { ... };
    ($t:ty, $val:expr) => { ... };
}

Macro to create a NonNegative value.

Returns Result<NonNegative<T>, NonNegativeError>.

Usage:

• nonneg!(value) infers type and creates a NonNegative from value.
• nonneg!(Type) creates a default zero value of that type.
• nonneg!(Type, value) creates a NonNegative of the specified type.