Struct Backtracker 

pub struct Backtracker { /* private fields */ }

A linear backtracking choice point over a fixed list of alternatives.

Models the choose/fail surface of non-deterministic control: each Backtracker::choose or Backtracker::fail commits to the next alternative, yielding BacktrackStep::Failed once they run out.

Implementations

impl Backtracker

pub fn new(alternatives: Vec<Ref>) -> Self

Builds a backtracker that walks alternatives in order.

pub fn choose(&mut self) -> BacktrackStep

Commits to the next alternative, or BacktrackStep::Failed if none remain.

pub fn fail(&mut self) -> BacktrackStep

Backtracks the current choice and advances to the next alternative; equivalent to Backtracker::choose.

Trait Implementations

impl Clone for Backtracker

fn clone(&self) -> Backtracker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Backtracker

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Backtracker

impl PartialEq for Backtracker

fn eq(&self, other: &Backtracker) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Backtracker