any_cmp

Support dynamic type comparisons.

The author of this crate is not good at English.
Forgive me if the document is hard to read.

What is this?

This crate provides traits that are comparable and can be dynamic types.

Mainly includes the following items.

• AnyEq - Like std::cmp::Eq.
• AnyHash - Like std::hash::Hash.
• AnyOrd - Like std::cmp::Ord.
• AnyPartialEq - Like std::cmp::PartialEq.
• AnyPartialOrd - Like std::cmp::PartialOrd.
• ObjHash - Trait that combines AnyEq and AnyHash.

Examples

Here is an example simple but useless.

let x = &42 as &dyn AnyEq;
let y = &42 as &dyn AnyEq;
let z = &"42" as &dyn AnyEq;
assert!(x == y);
assert!(x != z);

Here is an example of using dynamic types for HashMap keys.

let mut map = HashMap::<Box<dyn ObjHash>, String>::new();
map.insert(Box::new(false), "bool".to_string());
map.insert(Box::new(0), "int".to_string());
map.insert(Box::new(""), "string".to_string());

assert_eq!(map[&false as &dyn ObjHash], "bool");
assert_eq!(map[&0 as &dyn ObjHash], "int");
assert_eq!(map[&"" as &dyn ObjHash], "string");

What's New

v0.4.0

• Fix forgotten implementation.
• Add box upcasting methods (ex: as_any_eq_box).

v0.3.0

• must_use annotations are added at several locations.

v0.2.0

• Module upcast specs have slightly changed.