#cmp #hash #any

any_cmp

Support dynamic type comparisons

6 releases (3 breaking)

0.4.1 Jan 14, 2024
0.4.0 Nov 5, 2023
0.3.0 Oct 30, 2023
0.2.0 Sep 6, 2023
0.1.1 Sep 5, 2023

#1057 in Rust patterns

MIT/Apache

21KB
549 lines

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.

name summary
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

v0.4.1

  • Minor refactoring.

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.

No runtime deps