Function canrun::collections::lmap::subset

pub fn subset<K, V, A, B>(a: A, b: B) -> impl Goalwhere
    K: Unify + Eq + Hash + Debug,
    V: Unify + Debug,
    A: Into<Value<LMap<K, V>>>,
    B: Into<Value<LMap<K, V>>>,

Assert that LMap a is a subset of LMap b.

This means that all of the keys in a unify with keys in b AND the corresponding values also unify. This is the opposite of superset.

Example:

use canrun::{LVar, Query};
use canrun::lmap::{lmap, subset};

let x = LVar::new();
let goal = subset(lmap! {x => 2}, lmap! {1 => 2, 3 => 4});
let results: Vec<_> = goal.query(x).collect();
assert_eq!(results, vec![1]);