Trait fmt_cmp::FmtOrd[−][src]

pub trait FmtOrd: Display + Ord + FmtEq { }
Expand description

A marker trait for types whose ordering is the same as ordering between its Display representation.

When T implements FmtOrd, the following property must be upheld for all a: T and b: T:

assert_eq!(a.cmp(&b), (*format!("{}", a)).cmp(&format!("{}", b)));

In other words (assuming that no ill-defined specialization is involved):

a ⋛ b <-> a.to_string() ⋛ b.to_string()

Colloraries

From str: Ord and the above property, it follows that T satisfies Ord trait’s contract.

Examples

Integer primitives do not satisfy the property.

assert!(42 < 240);
// but...
assert!(42.to_string() > 240.to_string());

Wrapping any Display type with fmt_cmp::Cmp makes it FmtOrd:

assert!(fmt_cmp::Cmp(42) > fmt_cmp::Cmp(240));

Implementations on Foreign Types

Implementors