Trait canrun::core::Fork

pub trait Fork: 'static {
    // Required method
    fn fork(&self, state: &State) -> StateIter;
}

Fork a State into zero or more alternate states.

Added to a State with .fork().

Example:

use canrun::{Fork, Query, State, StateIter, Value};
use std::rc::Rc;

struct Is1or2 {
    x: Value<i32>,
}

impl Fork for Is1or2 {
    fn fork(&self, state: &State) -> StateIter {
        let s1 = state.clone().unify(&self.x, &Value::new(1));
        let s2 = state.clone().unify(&self.x, &Value::new(2));
        Box::new(s1.into_iter().chain(s2.into_iter()))
    }
}

let x = Value::var();
let state = State::new();
let state = state.fork(Is1or2 { x: x.clone() });
let results: Vec<_> = state.query(x).collect();
assert_eq!(results, vec![1, 2]);

Required Methods

fn fork(&self, state: &State) -> StateIter

Given a State, return an iterator of states that result from the fork operation.

Implementors

impl Fork for Any

impl Fork for Either

impl<F> Fork for Fwhere F: Fn(&State) -> StateIter + 'static,