Function canrun::collections::lvec::member

pub fn member<'a, I, IV, CV, D>(item: IV, collection: CV) -> Goal<'a, D> where
    I: UnifyIn<'a, D> + 'a,
    IV: IntoVal<I>,
    LVec<I>: UnifyIn<'a, D>,
    CV: IntoVal<LVec<I>>,
    D: DomainType<'a, I> + DomainType<'a, LVec<I>>, 

Create a Goal that attempts to unify a Val<T> with any of the items in a LVec<T>.

This goal will fork the state for each match found.

Examples:

use canrun::{Goal, val, var, all, unify, lvec, example::Collections};

let x = var();
let xs = var();
let goal: Goal<Collections> = all![
    unify(x, 1),
    unify(xs, lvec![1, 2, 3]),
    lvec::member(x, xs),
];
let results: Vec<_> = goal.query(x).collect();
assert_eq!(results, vec![1]);

use canrun::{lvec, example::Collections};
let x = var();
let goal: Goal<Collections> = all![
    lvec::member(x, lvec![1, 2, 3]),
];
let results: Vec<_> = goal.query(x).collect();
assert_eq!(results, vec![1, 2, 3]);