Enum DistanceDirection 

pub enum DistanceDirection {
    Forward,
    Backward,
    Symmetric,
}

Determines how the distance propagates through the rule RHS.

Variants

Forward

The distance propagates forward.

Example

A ::= B C D

The distance to C is:

A ::= 1 B 0 C null D null

We find it like so:

use cfg_grammar::Cfg;
use cfg_predict_distance::{MinimalDistance, DistanceDirection};
let mut cfg = Cfg::new();
let [a, b, c, d] = cfg.sym();
cfg.set_roots([a]);
cfg.rule(a).rhs([b, c, d]);
let mut distance = MinimalDistance::new(&cfg);
let result = distance.minimal_distances(&[(0, 1)], DistanceDirection::Forward);
let expected = vec![Some(1), Some(0), None, None];
assert_eq!(result, &[expected]);

Backward

The distance propagates only backwards.

Symmetric

The distance propagates both ways thorughout the RHS.

Trait Implementations

impl Clone for DistanceDirection

fn clone(&self) -> DistanceDirection

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for DistanceDirection