Macro canrun::goals::all

macro_rules! all {
    ($($item:expr),* $(,)?) => { ... };
}

Create a goal that only succeeds if all sub-goals succeed.

This is essentially an "AND" operation on a vector of goals. The resulting state will be the result of the combining all of the sub-goals.

If the any goal fails, the rest of the goals will not be attempted.

Examples

Multiple successful goals allow values to flow between vars:

use canrun::{Goal, all, unify, var};
use canrun::example::I32;

let x = var();
let y = var();
let goal: Goal<I32> = all![unify(y, x), unify(1, x), unify(y, 1)];
let result: Vec<_> = goal.query((x, y)).collect();
assert_eq!(result, vec![(1, 1)])

A failing goal will cause the entire goal to fail:

let goal: Goal<I32> = all![unify(2, x), unify(1, x), unify(y, x)];
let result: Vec<_> = goal.query(x).collect();
assert_eq!(result, vec![]) // Empty result