fast-map

A small library and custom derive to create a map-like struct that uses match expressions to get and insert values.

If you know your keys at compile-time, this library will likely be faster than HashMap for supported map operations.

Provides the following operations on the wrapping struct (via derive macros):

• MyMap::get, returns Result<Option<&V>, Error>
• MyMap::get_mut, returns Result<Option<&mut V>, Error>
• MyMap::insert, returns Result<Option<V>, Error>, where V is the old value if one exists
• MyMap::remove, returns Result<Option<V>, Error>
• MyMap::values, returns an iterator over &Vs

Usage

```rust

fn main() { pub enum A { A, B, C, D };

#[derive(Default, fast_map::FastMap)]
#[fast_map(keys(A::A, A::B, A::C, A::D))]
struct Foo(fast_map::Map4<A, String>);

let mut foo = Foo::default();

foo.insert(A::B, "B".into()).unwrap();

assert_eq!(foo.get(A::B).unwrap(), Some(&"B".to_string()));

assert_eq!(foo.get(A::C).unwrap(), None);

foo.insert(A::C, "C".into()).unwrap();

assert_eq!(foo.values().collect::<Vec<_>>().len(), 2);

} ```

Changelog

0.2.0

• Removed easy and strict MapLike traits. It's better to handle unknown keys explicitly, even for gets.
• Added get_mut operation to the wrapping struct

Current version: 0.2.0

License: MIT