Function proto_vulcan::relation::cons

pub fn cons<U, E, G>(
    first: LTerm<U, E>, 
    rest: LTerm<U, E>, 
    out: LTerm<U, E>
) -> InferredGoal<U, E, G> where
    U: User,
    E: Engine<U>,
    G: AnyGoal<U, E>, 

A relation such that the out parameter is equal to rest parameter appended to first parameter. The first parameter is the head of the list out and the rest is the tail.

Example

extern crate proto_vulcan;
use proto_vulcan::prelude::*;
use proto_vulcan::relation::cons;
fn main() {
    let query = proto_vulcan_query!(|q| {
        cons(1, [2, 3], q)
    });
    assert!(query.run().next().unwrap().q == lterm!([1, 2, 3]));
}