Indexical is a library for conveniently and efficiently working with indexed collections of objects. "Indexed" means that the domain of objects is finite, and you can assign a numeric index to each object. This enables the use of efficient data structures like bit-sets.
Indexical is a layer on top of existing bit-set libraries like bitvec
and rustc_index::bit_set.
Those data structures only "understand" raw indexes, not the objects represented by the index.
Indexical provides utilities for converting between the object domain and the index domain.
use indexical::{IndexedDomain, IndexedValue, bitset::bitvec::IndexSet};
use std::rc::Rc;
// 1. Define a custom type.
#[derive(PartialEq, Eq, Clone, Hash)]
pub struct MyString(String);
// 2. Define a new index for your custom type.
indexical::define_index_type! {
pub struct StringIndex for MyString = u32;
}
// 3. Create an immutable indexed domain from a collection of objects.
// By default this is Rc-wrapped, but you can also use Arc or &-refs.
let domain = Rc::new(IndexedDomain::from_iter([
MyString(String::from("Hello")), MyString(String::from("world"))
]));
// 4. Now you can make a set! Notice how you can pass either a `MyString`
// or a `StringIndex` to `set.insert(..)` and `set.contains(..)`.
let mut set = IndexSet::new(&domain);
set.insert(MyString(String::from("Hello")));
set.insert(StringIndex::from_usize(1));
assert!(set.contains(&MyString(String::from("world"))));