Enum Nav 

pub enum Nav {
    Epsilon,
    Stay,
    StayExact,
    Next,
    NextSkip,
    NextExact,
    Down,
    DownSkip,
    DownExact,
    Up(u8),
    UpSkipTrivia(u8),
    UpExact(u8),
}

Navigation command for VM execution.

Variants

Epsilon

Epsilon transition: pure control flow, no cursor movement or node check. Used for branching, quantifier loops, and effect-only transitions.

Stay

Stay at current position.

StayExact

Stay at current position, exact match only (no continue_search).

Next

NextSkip

NextExact

Down

DownSkip

DownExact

Up(u8)

UpSkipTrivia(u8)

UpExact(u8)

Implementations

impl Nav

pub fn from_byte(b: u8) -> Self

Decode from bytecode byte.

Byte layout:

• Bits 7-6: Mode (00=Standard, 01=Up, 10=UpSkipTrivia, 11=UpExact)
• Bits 5-0: Payload (enum value for Standard, level count for Up variants)

pub fn to_byte(self) -> u8

Encode to bytecode byte.

pub fn to_exact(self) -> Self

Convert navigation to its exact variant (no search loop).

Used by alternation branches which should match at their exact cursor position only - the search among positions is owned by the parent context (quantifier’s skip-retry, sequence advancement).

Trait Implementations

impl Clone for Nav

fn clone(&self) -> Nav

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Nav

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

Formats the value using the given formatter.

impl Default for Nav

fn default() -> Nav

Returns the “default value” for a type.

impl PartialEq for Nav

fn eq(&self, other: &Nav) -> 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 Copy for Nav

impl Eq for Nav

impl StructuralPartialEq for Nav