mona: Transform nested container types in Rust

Usage

The crate provides the .transpose() and .flatten() on nested container types.

.transpose() exchanges the inner and outer containers types. For example,

• Vec<Vec<T>> -> Option<Vec<Vec<T>>>
• Vec<HashMap<K, V>> -> Option<HashMap<K, Vec<V>>>
• HashMap<K, Vec<V>> -> HashMap<K, Vec<V>>
• Result<Result<T, E>, F> -> Result<Result<T, F>, E>
• Option<Option<T>> -> Option<Option<T>>

.flatten() merges the inner and outer container types. For example,

• Vec<Vec<T>> -> Vec<T>
• HashMap<K, HashMap<L, V>> -> HashMap<(K, L), V>
• HashMap<K, Vec<V>> -> HashMap<(K, usize), V>
• Vec<HashMap<K, V>> -> HashMap<(usize, K), V>

This is an example usage of .transpose and .flatten().

use mona::prelude::*;

let vec_of_vec = vec![vec![1, 2, 3], vec![4, 5, 6]];

assert_eq!(
    vec_of_vec.clone().transpose(),
    Some(vec![vec![1, 4], vec![2, 5], vec![3, 6]])
);

assert_eq!(vec_of_vec.flatten(), vec![1, 2, 3, 4, 5, 6]);

License

MIT license. See LICENSE.txt.