#mixed

mixed_array

Construct arrays of mixed types

2 releases

0.1.1 Jul 16, 2023
0.1.0 Jul 16, 2023

#1360 in Rust patterns


Used in sync_stream

MIT/Apache

8KB
153 lines

Mixed Array

Construct arrays of mixed types. Generic enums are created for up to 12 unique types. A macro to generate an array using the correct size macro is provided.

Usage

  1. Include in the Cargo.toml file:
[dependencies]
mixed_array = "0.1.0"
  1. Import and use the mixed_array macro to create an array of items
use mixed_array::mixed_array;
use std::cmp::Ordering;

// define a struct with a generic so the generated types are different as a demo
#[derive(Clone, Debug)]
struct Item<T> {
    id: u32,
    value: T,
}

impl<T> Eq for Item<T> {}

//implement ordering for our item for any T
impl<T, B> PartialEq<Item<B>> for Item<T> {
    fn eq(&self, other: &Item<B>) -> bool {
        self.id == other.id
    }
}

impl<T, B> PartialOrd<Item<B>> for Item<T> {
    fn partial_cmp(&self, other: &Item<B>) -> Option<Ordering> {
        self.id.partial_cmp(&other.id)
    }
}

impl<T> Ord for Item<T> {
    fn cmp(&self, other: &Self) -> Ordering {
        self.id.cmp(&other.id)
    }
}

fn main() {
    //can now create an array of different types
    let items = mixed_array![
        Item::<&str> {
            id: 100,
            value: "blah",
        },
        Item::<u32> {
            id: 200,
            value: 123,
        },
        Item::<f32> {
            id: 300,
            value: 9.3,
        },
    ];

    dbg!(items.into_iter().min());
}

Alternatives

  • Frunk - HList - Provides a `hlist`` macro to construct a recursive custom data type used for storing different types (replaces using an array), easy conversion to tuples.

Dependencies

~225–670KB
~16K SLoC